Bump DeterminateSystems/flake-checker-action from 8 to 9

Bumps [DeterminateSystems/flake-checker-action](https://github.com/determinatesystems/flake-checker-action) from 8 to 9.
- [Release notes](https://github.com/determinatesystems/flake-checker-action/releases)
- [Commits](DeterminateSystems/flake-checker-action@v8...v9)

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

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

.github/workflows/check.yml

@@ -18,7 +18,7 @@ jobs:
           nix_path: nixpkgs=channel:nixos-unstable
 
       - name: Nix Flake Checker
-        uses: DeterminateSystems/flake-checker-action@v8
+        uses: DeterminateSystems/flake-checker-action@v9
         with:
           fail-mode: true