ci: show diff for toml_format

- The `--diff` parameter isn't available via npx
- Also runs faster

Author: xtqqczze

.github/workflows/ci.yml

@@ -50,11 +50,12 @@ jobs:
   toml_format:
     runs-on: ubuntu-latest
     steps:
+      - uses: taiki-e/install-action@taplo
       - name: Clone repository
         uses: actions/checkout@v5
 
       - name: Check
-        run: npx --yes @taplo/cli fmt --check
+        run: taplo fmt --check --diff