[github-workflows]: Bump actions/checkout from 2 to 4 (#30)

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2...v4)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/checks.yaml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
 
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       # cache the ASDF directory, using the values from .tool-versions
       - name: ASDF cache
         uses: actions/cache@v3
@@ -28,7 +28,7 @@ jobs:
     needs: setup
     steps:
 
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: ASDF cache
         uses: actions/cache@v3
         with:

.github/workflows/deploy-ecs.yml

@@ -36,7 +36,7 @@ jobs:
     environment: ${{ inputs.environment }}
     concurrency: ${{ inputs.environment }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: mbta/actions/build-push-ecr@v2
         id: build-push
         with:

.github/workflows/deploy-on-prem.yml

@@ -100,7 +100,7 @@ jobs:
           role-to-assume: ${{ secrets.aws-role-arn }}
           aws-region: ${{ inputs.aws-region }}
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Calculate Docker tag
         id: docker
         run: |