fix lint error

Feiyang1 · Feiyang1 · commit a9a380d0f0be · 2021-02-22T11:29:24.000-08:00
diff --git a/packages/database/exp-types/index.d.ts b/packages/database/exp-types/index.d.ts
@@ -15,6 +15,7 @@
  * limitations under the License.
  */
 
+// eslint-disable-next-line import/no-extraneous-dependencies
 import { FirebaseApp } from '@firebase/app';
 
 /**
