actually exit with non-zero if format mismatches

kcd-scripts format runs with --write by default.
So we end up with --check --write which always exits with 0 if the formatting was succesful

Author: eps1lon

.github/workflows/validate.yml

@@ -40,7 +40,7 @@ jobs:
 
       # TODO: Can be removed if https://github.com/kentcdodds/kcd-scripts/pull/146 is released
       - name: Verify format (`npm run format` committed?)
-        run: npm run format -- --check
+        run: npm run format -- --check --no-write
 
       - name: ▶️ Run validate script
         run: npm run validate