[github] bump actions/checkout from 3 to 4 (#16)

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...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/buildx.yaml

@@ -25,7 +25,7 @@ jobs:
       WORKING_DIRECTORY: ${{ github.event.inputs.image_name }}/${{ github.event.inputs.image_tag }}
     steps:
     - name: Checkout
-      uses: actions/checkout@v3  # See https://github.com/actions/checkout
+      uses: actions/checkout@v4  # See https://github.com/actions/checkout
 
     - name: Validate event inputs
       uses: actions/github-script@v6  # See https://github.com/actions/github-script

.github/workflows/mirror.yaml

@@ -11,7 +11,7 @@ jobs:
     name: gitlab
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         fetch-depth: 0
     - name: Push to gitlab