chore(deps): update actions/checkout action to v6 (#85)

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

Author: renovate[bot]

.github/workflows/check.yaml

@@ -31,7 +31,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           ref: ${{ inputs.ref && inputs.ref || github.ref_name }}
           persist-credentials: false

.github/workflows/update-flake-lock.yaml

@@ -13,7 +13,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - uses: cachix/install-nix-action@v31
         with: