Run gofmt via python, easier to debug

.github/workflows/ci.py

@@ -130,6 +130,11 @@ def main():
         package_kitty()
     elif action == 'test':
         test_kitty()
+    elif action == 'gofmt':
+        q = subprocess.check_output('gofmt -s -l tools version.go'.split())
+        if q.strip():
+            print(q.decode())
+            raise SystemExit(1)
     else:
         raise SystemExit(f'Unknown action: {action}')