build(deps): bump the actions group with 2 updates

Bumps the actions group with 2 updates: [nixbuild/nix-quick-install-action](https://github.com/nixbuild/nix-quick-install-action) and [nix-community/cache-nix-action](https://github.com/nix-community/cache-nix-action).


Updates `nixbuild/nix-quick-install-action` from 29 to 30
- [Release notes](https://github.com/nixbuild/nix-quick-install-action/releases)
- [Changelog](https://github.com/nixbuild/nix-quick-install-action/blob/master/RELEASE)
- [Commits](https://github.com/nixbuild/nix-quick-install-action/compare/v29...v30)

Updates `nix-community/cache-nix-action` from 5 to 6
- [Release notes](https://github.com/nix-community/cache-nix-action/releases)
- [Changelog](https://github.com/nix-community/cache-nix-action/blob/main/RELEASES.md)
- [Commits](https://github.com/nix-community/cache-nix-action/compare/v5...v6)

---
updated-dependencies:
- dependency-name: nixbuild/nix-quick-install-action
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions
- dependency-name: nix-community/cache-nix-action
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/nix.yaml

@@ -20,9 +20,9 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
-      - uses: nixbuild/nix-quick-install-action@v29
+      - uses: nixbuild/nix-quick-install-action@v30
       - name: Restore and cache Nix store
-        uses: nix-community/cache-nix-action@v5
+        uses: nix-community/cache-nix-action@v6
         with:
           primary-key: nix-${{ runner.os }}-${{ hashFiles('**/*.nix') }}
           restore-prefixes-first-match: nix-${{ runner.os }}-