chore(ci)(deps): bump DeterminateSystems/flake-checker-action

Bumps [DeterminateSystems/flake-checker-action](https://github.com/determinatesystems/flake-checker-action) from 5 to 7.
- [Release notes](https://github.com/determinatesystems/flake-checker-action/releases)
- [Commits](DeterminateSystems/flake-checker-action@v5...v7)

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

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

.github/workflows/nix.yml

@@ -21,7 +21,7 @@ jobs:
         uses: DeterminateSystems/magic-nix-cache-action@v3
 
       - name: Check Nix flake inputs
-        uses: DeterminateSystems/flake-checker-action@v5
+        uses: DeterminateSystems/flake-checker-action@v7
         with:
           ignore-missing-flake-lock: false
           fail-mode: true