ci(nix): fix cachix error

.github/workflows/build.yml

@@ -58,14 +58,14 @@ jobs:
     steps:
       - uses: actions/checkout@v3
 
-      - uses: cachix/install-nix-action@v17
+      - uses: cachix/install-nix-action@v20
         with:
           install_url: https://nixos.org/nix/install
           extra_nix_config: |
             auto-optimise-store = true
             experimental-features = nix-command flakes
 
-      - uses: cachix/cachix-action@v11
+      - uses: cachix/cachix-action@v12
         with:
           name: jakestanger
           signingKey: '${{ secrets.CACHIX_SIGNING_KEY }}'

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

@@ -13,7 +13,7 @@ jobs:
         uses: actions/checkout@v2
 
       - name: Install Nix
-        uses: cachix/install-nix-action@v16
+        uses: cachix/install-nix-action@v20
         with:
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}