Update actions/checkout action to v6 (#427)

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

.github/workflows/black.yml

@@ -6,5 +6,5 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: psf/black@stable

.github/workflows/pre-commit.yml

@@ -12,7 +12,7 @@ jobs:
   pre-commit:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-python@v6
         with:
           python-version: ${{ env.PYTHON_VERSION }}

.github/workflows/push-container.yml

@@ -9,7 +9,7 @@ jobs:
     name: Push to container registry
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Prepare
         id: prep

.github/workflows/pylint.yml

@@ -9,7 +9,7 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-python@v6
         with:
           python-version: ${{ env.PYTHON_VERSION }}