chore(deps): bump actions/checkout from 4 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...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] <[email protected]>

Author: dependabot[bot]

.github/workflows/containers.yml

@@ -30,7 +30,7 @@ jobs:
         steps:
             # Checkout push-to-registry action GitHub repository
             - name: Checkout Push to Registry action
-              uses: actions/checkout@v4
+              uses: actions/checkout@v6
 
             - name: Gather environment variables
               run: echo "IMAGE_NAME=$(echo ${{ matrix.containerfile }} | cut -d . -f 1)" >> $GITHUB_ENV