build(deps): bump cachix/install-nix-action in /.github/workflows

Bumps [cachix/install-nix-action](https://github.com/cachix/install-nix-action) from 17 to 26.
- [Release notes](https://github.com/cachix/install-nix-action/releases)
- [Commits](cachix/install-nix-action@v17...v26)

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

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

.github/workflows/check-nixos-config.yaml

@@ -9,7 +9,7 @@ jobs:
     steps:
     - uses: actions/checkout@v3
     - name: Install Nix
-      uses: cachix/install-nix-action@v17
+      uses: cachix/install-nix-action@v26
       with:
         extra_nix_config: |
           experimental-features = nix-command flakes