chore(deps): bump cachix/install-nix-action from 20 to 21 (#333)

Bumps [cachix/install-nix-action](https://github.com/cachix/install-nix-action) from 20 to 21.
- [Release notes](https://github.com/cachix/install-nix-action/releases)
- [Commits](https://github.com/cachix/install-nix-action/compare/v20...v21)

---
updated-dependencies:
- dependency-name: cachix/install-nix-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/pages.yml

@@ -14,7 +14,7 @@ jobs:
       SSH_AUTH_SOCK: /tmp/ssh_agent.sock
     steps:
     - uses: actions/checkout@v3
-    - uses: cachix/install-nix-action@v20
+    - uses: cachix/install-nix-action@v21
     - uses: cachix/cachix-action@v12
       with:
         name: crane

.github/workflows/test.yml

@@ -37,7 +37,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3
-    - uses: cachix/install-nix-action@v20
+    - uses: cachix/install-nix-action@v21
       with:
         install_url: ${{ matrix.install_url }}
     - uses: cachix/cachix-action@v12
@@ -70,7 +70,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v3
-    - uses: cachix/install-nix-action@v20
+    - uses: cachix/install-nix-action@v21
       with:
         install_url: ${{ matrix.install_url }}
     - uses: cachix/cachix-action@v12
@@ -90,7 +90,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3
-    - uses: cachix/install-nix-action@v20
+    - uses: cachix/install-nix-action@v21
     - uses: cachix/cachix-action@v12
       with:
         name: deadnix
@@ -101,6 +101,6 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3
-    - uses: cachix/install-nix-action@v20
+    - uses: cachix/install-nix-action@v21
     - name: check formatting
       run: nix fmt -- --check .

.github/workflows/update-flake.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3
-    - uses: cachix/install-nix-action@v20
+    - uses: cachix/install-nix-action@v21
       with:
         extra_nix_config: |
           access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}