chore(deps): bump DeterminateSystems/flake-checker-action from 9 to 12

Bumps [DeterminateSystems/flake-checker-action](https://github.com/determinatesystems/flake-checker-action) from 9 to 12.
- [Release notes](https://github.com/determinatesystems/flake-checker-action/releases)
- [Commits](DeterminateSystems/flake-checker-action@v9...v12)

---
updated-dependencies:
- dependency-name: DeterminateSystems/flake-checker-action
  dependency-version: '12'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/flake-checker.yml

@@ -18,4 +18,4 @@ jobs:
           fetch-depth: 0
       - uses: DeterminateSystems/nix-installer-action@v19
       - uses: DeterminateSystems/magic-nix-cache-action@v8
-      - uses: DeterminateSystems/flake-checker-action@v9
+      - uses: DeterminateSystems/flake-checker-action@v12