build(deps): bump cachix/cachix-action in /.github/actions/setup-nix

Bumps [cachix/cachix-action](https://github.com/cachix/cachix-action) from 12 to 13.
- [Release notes](https://github.com/cachix/cachix-action/releases)
- [Commits](cachix/cachix-action@v12...v13)

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

Signed-off-by: dependabot[bot] <[email protected]>

.github/actions/setup-nix/action.yaml

@@ -24,7 +24,7 @@ runs:
         restore-keys: |
           cache-nix-${{ runner.os }}-common-
         restore-key-hit: true
-    - uses: cachix/cachix-action@v12
+    - uses: cachix/cachix-action@v13
       with:
         name: postgrest
         authToken: ${{ inputs.authToken }}