Switch to Nix Installer Action

.github/workflows/ci.yml

@@ -12,6 +12,6 @@ jobs:
         with:
           fetch-depth: 0
       - name: Install Nix
-        uses: cachix/install-nix-action@v18
+        uses: DeterminateSystems/nix-installer-action@main
       - name: Shellcheck
         run: nix-shell --run 'shellcheck $(find . -type f -name "*.sh" -executable)'

.github/workflows/update.yml

@@ -2,7 +2,7 @@ name: update-flake-lock
 on:
   workflow_dispatch:
   schedule:
-    - cron: '0 0 * * 0'
+    - cron: "0 0 * * 0"
 
 jobs:
   lockfile:
@@ -11,9 +11,6 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v3
       - name: Install Nix
-        uses: cachix/install-nix-action@v18
-        with:
-          extra_nix_config: |
-            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
+        uses: DeterminateSystems/nix-installer-action@main
       - name: Update flake.lock
         uses: ./.