ci: Add codeowners file to finch (#501)

Issue #, if available:
N/A.
*Description of changes:*
- Add `CODEOWNERS` file to finch to ensure that [release-please
PR](#483) which modifies`
CHANGELOG.md` has to be reviewed and approved by a member of
`@runfinch/dev-team` in order to kick off a finch release.
- Ensures that any changes to `.github` directory requires approval from
`@runfinch/dev-team`, i.e even modifications to `CODEOWNERS` would
require an approval from the team.
- Modifies `ci.yaml` to not run CI checks on `CODEOWNERS` file. 


*Testing done:*
Yes, on personal repo. 
See code owners setting in
[CODEOWNERS](https://github.com/vsiravar/github-actions-experiments/blob/main/.github/CODEOWNERS)
and test [requesting review from code
owner](vsiravar/github-actions-experiments#22)


- [X] I've reviewed the guidance in CONTRIBUTING.md


#### License Acceptance

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license.

Signed-off-by: Vishwas Siravara <siravara@amazon.com>

.github/CODEOWNERS

@@ -0,0 +1,5 @@
+# CHANGELOG generated by release-please action has to be approved by dev-team before creating a release.
+/CHANGELOG.md @runfinch/dev-team
+
+# Any changes to github workflows requires dev-team approval
+/.github/ @runfinch/dev-team

.github/workflows/ci.yaml

@@ -8,12 +8,14 @@ on:
     paths-ignore:
       - '**.md'
       - 'contrib/**'
+      - '.github/CODEOWNERS'
   pull_request:
     branches:
       - main
     paths-ignore:
       - '**.md'
       - 'contrib/**'
+      - '.github/CODEOWNERS'
 permissions:
   id-token: write
   contents: write