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

.github/workflows/ci.yml

@@ -27,7 +27,7 @@ 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/|alembic/|/__init__.py'"
@@ -57,7 +57,7 @@ jobs:
           POSTGRES_PASSWORD: root
           POSTGRES_DB: fastapi
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - uses: actions/setup-python@v5
       with:
         python-version: 3.13
@@ -79,7 +79,7 @@ jobs:
       version: ${{ steps.git_version.outputs.version }}
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           fetch-tags: true
           ref: ${{ github.ref }}
@@ -110,7 +110,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Log in to the Container registry
         uses: docker/login-action@v3