Bump cachix/install-nix-action from 15 to 16 (#14)

Bumps [cachix/install-nix-action](https://github.com/cachix/install-nix-action) from 15 to 16.
- [Release notes](https://github.com/cachix/install-nix-action/releases)
- [Commits](cachix/install-nix-action@v15...v16)

---
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]>

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

Author: dependabot[bot]

.github/workflows/cli.yml

@@ -42,7 +42,7 @@ jobs:
           - macos-10.15
     steps:
       - uses: actions/checkout@v2
-      - uses: cachix/install-nix-action@v15
+      - uses: cachix/install-nix-action@v16
         with:
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}