feat(deps): update actions/checkout action to v6

.github/workflows/ci.yml

@@ -19,7 +19,7 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - uses: psf/black@stable
       with:
         options: "-l 100 --exclude '/.venv/|/__init__.py'"
@@ -35,7 +35,7 @@ jobs:
     runs-on: ubuntu-latest
     needs: lint
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: actions/setup-python@v5
         with:
           python-version: '3.13'
@@ -55,7 +55,7 @@ jobs:
       contents: write # for the tags
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           fetch-tags: true
           ref: ${{ github.ref_name }}