chore(deps): update cachix/install-nix-action digest to a809471

Author: renovate[bot]

.github/workflows/ci.yaml

@@ -10,5 +10,5 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
-    - uses: cachix/install-nix-action@91a071959513ca103b54280ac0bef5b825791d4d # v31
+    - uses: cachix/install-nix-action@a809471b5c7c913aa67bec8f459a11a0decc3fce # v31
     - run: ./ci.sh