Update actions/checkout action to v7

Author: renovate[bot]

.github/workflows/lint.yaml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
       - uses: cachix/install-nix-action@8aa03977d8d733052d78f4e008a241fd1dbf36b3 # v31
         with:
           nix_path: nixpkgs=channel:nixos-unstable

.github/workflows/update-flakes.yaml

@@ -18,7 +18,7 @@ jobs:
       flake-inputs: ${{ steps.get-flake-inputs.outputs.flake-inputs }}
 
     steps:
-      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
         with:
           sparse-checkout: flake.lock
           persist-credentials: false
@@ -38,7 +38,7 @@ jobs:
       matrix: ${{ fromJson(needs.get-flake-inputs.outputs.flake-inputs) }}
 
     steps:
-      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
           persist-credentials: false