use latest install nix action

Author: dundalek

.github/workflows/test.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3
-    - uses: cachix/install-nix-action@v19
+    - uses: cachix/install-nix-action@master
       with:
         nix_path: nixpkgs=channel:nixos-unstable
     - uses: DeterminateSystems/magic-nix-cache-action@main