chore(deps): update actions/checkout action to v7

Author: renovate[bot]

.github/workflows/nix.yml

@@ -27,7 +27,7 @@ jobs:
       #     name: cclib
       #     authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
       # Checkout of the current head in the working dir
-      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10  # v6
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7
         with:
           persist-credentials: false
       - name: Check nix flake

.github/workflows/pre-commit.yml

@@ -16,7 +16,7 @@ jobs:
     name: Run pre-commit
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10  # v6
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7
         with:
           persist-credentials: false
       - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405  # v6