build(deps): bump cachix/install-nix-action from 30 to 31 (#3474)

Author: flavorjones

.github/workflows/ci.yml

@@ -297,7 +297,7 @@ jobs:
       - uses: actions/checkout@v4
         with:
           submodules: true
-      - uses: cachix/install-nix-action@v30
+      - uses: cachix/install-nix-action@v31
         with:
           nix_path: nixpkgs=channel:nixos-24.11
       - run: nix-shell --packages ruby bundler --run 'bundle install'