build(deps): bump actions/checkout from 3 to 4

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] <[email protected]>

.github/workflows/ci.yaml

@@ -33,7 +33,7 @@ jobs:
       image: ghcr.io/go-debos/test-containers/${{matrix.variant}}:main
     steps:
     - name: Checkout code
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: Test build
       run: go build -o debos cmd/debos/debos.go
@@ -50,7 +50,7 @@ jobs:
     needs: test
     steps:
       - name: Repository checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Setup Docker buildx
         uses: docker/setup-buildx-action@v3
@@ -86,7 +86,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Repository checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Setup Docker buildx
         uses: docker/setup-buildx-action@v3
@@ -140,7 +140,7 @@ jobs:
     name: ${{matrix.test.name}} on ${{matrix.backend.name}}
     steps:
       - name: Repository checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Install QEMU emulation binaries
         if: matrix.backend.install_qemu
@@ -199,7 +199,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Extract Docker metadata
         id: meta
@@ -277,7 +277,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Extract Docker metadata
         id: meta