Bump actions/checkout from 5 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 5 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/release.yml

@@ -12,7 +12,7 @@ jobs:
     permissions:
       contents: read
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Build the Docker image
         run: docker build .
 
@@ -23,7 +23,7 @@ jobs:
       contents: read
       packages: write
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Publish to Registry
         if: ${{ github.actor != 'dependabot[bot]' }}
         uses: elgohr/Publish-Docker-Github-Action@main
@@ -39,7 +39,7 @@ jobs:
     permissions:
       contents: read
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Publish to Registry
         if: ${{ github.actor != 'dependabot[bot]' }}
         uses: elgohr/Publish-Docker-Github-Action@main
@@ -57,7 +57,7 @@ jobs:
       contents: read
       packages: write
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Set up Docker Buildx for Multi-Arch Build
         uses: docker/setup-buildx-action@v3
       - name: Publish to Registry
@@ -80,7 +80,7 @@ jobs:
       - integration-test-dockerhub
       - integration-test-multi-arch
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           token: ${{ secrets.PUBLISH_TOKEN }} # for pushing to protected branch
       - name: Publish new version