chore(deps): update actions/checkout action to v6 (#56)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/build_container.yml

@@ -17,7 +17,7 @@ jobs:
       packages: write
     steps:
       - name: Source checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Get commitlint version
         id: get_version

.github/workflows/ci.yaml

@@ -21,7 +21,7 @@ jobs:
       contents: read
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Build image
         uses: docker/build-push-action@v6

.github/workflows/markdownlint.yml

@@ -17,7 +17,7 @@ jobs:
   markdown-lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: DavidAnson/markdownlint-cli2-action@v21
         with:
           globs: '**/*.md'

.github/workflows/security_scanning.yml

@@ -19,7 +19,7 @@ jobs:
       security-events: write
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Build local container
         uses: docker/build-push-action@v6

.github/workflows/shellcheck.yml

@@ -22,7 +22,7 @@ jobs:
       actions: read
     steps:
     - name: Repository checkout
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       with:
         # Differential ShellCheck requires full git history
         fetch-depth: 0