chore(deps): update cachix/install-nix-action action to v31

Author: renovate[bot]

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

@@ -13,7 +13,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29 # v4
       - name: Install Nix
-        uses: cachix/install-nix-action@ba0dd844c9180cbf77aa72a116d6fbc515d0e87b # v27
+        uses: cachix/install-nix-action@9280e7aca88deada44c930f1e2c78e21c3ae3edd # v31
         with:
           github_access_token: ${{ secrets.GITHUB_TOKEN }}
           extra_nix_config: |