Fix AuthActionHooks type from 'void' to 'Promise<void>'

Author: kqito

auth/types.ts

@@ -1,7 +1,7 @@
 import firebase from 'firebase/app';
 
 export type AuthActionHook<T, E> = [
-  (email: string, password: string) => void,
+  (email: string, password: string) => Promise<void>,
   T | undefined,
   boolean,
   E | undefined