chore(deps): update cachix/cachix-action action to v16

Author: renovate[bot]

.github/workflows/gh-pages.yml

@@ -18,7 +18,7 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - uses: cachix/install-nix-action@v20
-      - uses: cachix/cachix-action@v12
+      - uses: cachix/cachix-action@v16
         with:
           name: numtide
           authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'