chore(deps): update actions/checkout action to v6 (#443)

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

Author: renovate[bot]

.github/workflows/main.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup uv
         uses: astral-sh/setup-uv@v7
@@ -41,7 +41,7 @@ jobs:
     needs: test
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Docker
         uses: docker/setup-buildx-action@v3
@@ -101,7 +101,7 @@ jobs:
     needs: test
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Docker
         uses: docker/setup-buildx-action@v3