build(deps): bump cachix/install-nix-action from V27 to 28 (helix-editor#11713)

Bumps [cachix/install-nix-action](https://github.com/cachix/install-nix-action) from V27 to 28. This release includes the previously tagged commit.
- [Release notes](https://github.com/cachix/install-nix-action/releases)
- [Commits](cachix/install-nix-action@V27...V28)

---
updated-dependencies:
- dependency-name: cachix/install-nix-action
  dependency-type: direct:production
...

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

Author: dependabot[bot]

.github/workflows/cachix.yml

@@ -14,7 +14,7 @@ jobs:
       uses: actions/checkout@v4
 
     - name: Install nix
-      uses: cachix/install-nix-action@V27
+      uses: cachix/install-nix-action@V28
 
     - name: Authenticate with Cachix
       uses: cachix/cachix-action@v15