Added optional configuration to keep squash merges tidy

[dms1981]

A reference to the issue / Description of it

No issue - but I've noted that our commit messages aren't always to the highest standard; GitHub can allow us to - by default - set the commit title & message in a squash merge to the PR title and concatenated commit messages by default

How does this PR fix the problem?

Sets the values for squash_merge_commit_message and squash_merge_commit_title.

How has this been tested?

Tested through local plan.

Deployment Plan / Instructions

Deploy through CI.

Checklist (check x in [ ] of list items)

• I have performed a self-review of my own code
• All checks have passed
• I have made corresponding changes to the documentation
• Plan and discussed how it should be deployed to PROD (If needed)

Additional comments (if any)

{Please write here}

[github-actions]

Trivy Scan Success

Show Output

```hcl

---

Trivy will check the following folders:
terraform/github/modules/repository
terraform/github

---

Running Trivy in terraform/github/modules/repository
2024-12-06T13:40:05Z INFO [vulndb] Need to update DB
2024-12-06T13:40:05Z INFO [vulndb] Downloading vulnerability DB...
2024-12-06T13:40:05Z INFO [vulndb] Downloading artifact... repo="public.ecr.aws/aquasecurity/trivy-db:2"
2024-12-06T13:40:07Z INFO [vulndb] Artifact successfully downloaded repo="public.ecr.aws/aquasecurity/trivy-db:2"
2024-12-06T13:40:07Z INFO [vuln] Vulnerability scanning is enabled
2024-12-06T13:40:07Z INFO [misconfig] Misconfiguration scanning is enabled
2024-12-06T13:40:07Z INFO [misconfig] Need to update the built-in checks
2024-12-06T13:40:07Z INFO [misconfig] Downloading the built-in checks...
160.80 KiB / 160.80 KiB [------------------------------------------------------] 100.00% ? p/s 100ms2024-12-06T13:40:10Z INFO [secret] Secret scanning is enabled
2024-12-06T13:40:10Z INFO [secret] If your scanning is slow, please try '--scanners vuln' to disable secret scanning
2024-12-06T13:40:10Z INFO [secret] Please see also https://aquasecurity.github.io/trivy/v0.58/docs/scanner/secret#recommendation for faster secret detection
2024-12-06T13:40:11Z INFO [terraform scanner] Scanning root module file_path="."
2024-12-06T13:40:11Z WARN [terraform parser] Variable values was not found in the environment or variable files. Evaluating may not work correctly. module="root" variables="description, name, topics"
2024-12-06T13:40:11Z INFO Number of language-specific files num=0
2024-12-06T13:40:11Z INFO Detected config files num=2
trivy_exitcode=0

---

Running Trivy in terraform/github
2024-12-06T13:40:11Z INFO [vuln] Vulnerability scanning is enabled
2024-12-06T13:40:11Z INFO [misconfig] Misconfiguration scanning is enabled
2024-12-06T13:40:11Z INFO [secret] Secret scanning is enabled
2024-12-06T13:40:11Z INFO [secret] If your scanning is slow, please try '--scanners vuln' to disable secret scanning
2024-12-06T13:40:11Z INFO [secret] Please see also https://aquasecurity.github.io/trivy/v0.58/docs/scanner/secret#recommendation for faster secret detection
2024-12-06T13:40:12Z INFO [terraform scanner] Scanning root module file_path="."
2024-12-06T13:40:12Z WARN [terraform parser] Variable values was not found in the environment or variable files. Evaluating may not work correctly. module="root" variables="github_token"
2024-12-06T13:40:14Z INFO [terraform executor] Ignore finding rule="aws-iam-no-user-attached-policies" range="testing-ci.tf:4-9"
2024-12-06T13:40:14Z INFO Number of language-specific files num=0
2024-12-06T13:40:14Z INFO Detected config files num=3
trivy_exitcode=0

</details> #### `Checkov Scan` Success
<details><summary>Show Output</summary>

```hcl

*****************************

Checkov will check the following folders:
terraform/github/modules/repository
terraform/github

*****************************

Running Checkov in terraform/github/modules/repository
Excluding the following checks: CKV_GIT_1,CKV_AWS_126,CKV2_AWS_38,CKV2_AWS_39
terraform scan results:

Passed checks: 2, Failed checks: 0, Skipped checks: 3


checkov_exitcode=0

*****************************

Running Checkov in terraform/github
Excluding the following checks: CKV_GIT_1,CKV_AWS_126,CKV2_AWS_38,CKV2_AWS_39
terraform scan results:

Passed checks: 97, Failed checks: 0, Skipped checks: 104


checkov_exitcode=0

CTFLint Scan Success

Show Output

*****************************

Setting default tflint config...
Running tflint --init...
Installing "terraform" plugin...
Installed "terraform" (source: github.com/terraform-linters/tflint-ruleset-terraform, version: 0.9.1)
tflint will check the following folders:
terraform/github/modules/repository
terraform/github

*****************************

Running tflint in terraform/github/modules/repository
Excluding the following checks: terraform_unused_declarations
tflint_exitcode=0

*****************************

Running tflint in terraform/github
Excluding the following checks: terraform_unused_declarations
tflint_exitcode=0

Trivy Scan Success

Show Output

*****************************

Trivy will check the following folders:
terraform/github/modules/repository
terraform/github

*****************************

Running Trivy in terraform/github/modules/repository
2024-12-06T13:40:05Z	INFO	[vulndb] Need to update DB
2024-12-06T13:40:05Z	INFO	[vulndb] Downloading vulnerability DB...
2024-12-06T13:40:05Z	INFO	[vulndb] Downloading artifact...	repo="public.ecr.aws/aquasecurity/trivy-db:2"
2024-12-06T13:40:07Z	INFO	[vulndb] Artifact successfully downloaded	repo="public.ecr.aws/aquasecurity/trivy-db:2"
2024-12-06T13:40:07Z	INFO	[vuln] Vulnerability scanning is enabled
2024-12-06T13:40:07Z	INFO	[misconfig] Misconfiguration scanning is enabled
2024-12-06T13:40:07Z	INFO	[misconfig] Need to update the built-in checks
2024-12-06T13:40:07Z	INFO	[misconfig] Downloading the built-in checks...
160.80 KiB / 160.80 KiB [------------------------------------------------------] 100.00% ? p/s 100ms2024-12-06T13:40:10Z	INFO	[secret] Secret scanning is enabled
2024-12-06T13:40:10Z	INFO	[secret] If your scanning is slow, please try '--scanners vuln' to disable secret scanning
2024-12-06T13:40:10Z	INFO	[secret] Please see also https://aquasecurity.github.io/trivy/v0.58/docs/scanner/secret#recommendation for faster secret detection
2024-12-06T13:40:11Z	INFO	[terraform scanner] Scanning root module	file_path="."
2024-12-06T13:40:11Z	WARN	[terraform parser] Variable values was not found in the environment or variable files. Evaluating may not work correctly.	module="root" variables="description, name, topics"
2024-12-06T13:40:11Z	INFO	Number of language-specific files	num=0
2024-12-06T13:40:11Z	INFO	Detected config files	num=2
trivy_exitcode=0

*****************************

Running Trivy in terraform/github
2024-12-06T13:40:11Z	INFO	[vuln] Vulnerability scanning is enabled
2024-12-06T13:40:11Z	INFO	[misconfig] Misconfiguration scanning is enabled
2024-12-06T13:40:11Z	INFO	[secret] Secret scanning is enabled
2024-12-06T13:40:11Z	INFO	[secret] If your scanning is slow, please try '--scanners vuln' to disable secret scanning
2024-12-06T13:40:11Z	INFO	[secret] Please see also https://aquasecurity.github.io/trivy/v0.58/docs/scanner/secret#recommendation for faster secret detection
2024-12-06T13:40:12Z	INFO	[terraform scanner] Scanning root module	file_path="."
2024-12-06T13:40:12Z	WARN	[terraform parser] Variable values was not found in the environment or variable files. Evaluating may not work correctly.	module="root" variables="github_token"
2024-12-06T13:40:14Z	INFO	[terraform executor] Ignore finding	rule="aws-iam-no-user-attached-policies" range="testing-ci.tf:4-9"
2024-12-06T13:40:14Z	INFO	Number of language-specific files	num=0
2024-12-06T13:40:14Z	INFO	Detected config files	num=3
trivy_exitcode=0

[markgov]

LGTM