fix: duplicated Dispatch definition (not allowed in ts 3.7) (#2250)

Author: xc1427

packages/dva/index.d.ts

@@ -3,14 +3,17 @@ import {
   Action,
   AnyAction,
   ReducersMapObject,
-  Dispatch,
   MiddlewareAPI,
   StoreEnhancer,
   bindActionCreators
 } from 'redux';
 
 import { History } from "history";
 
+export interface Dispatch<A extends Action = AnyAction> {
+  <T extends A>(action: T): Promise<any> | T;
+}
+
 export interface onActionFunc {
   (api: MiddlewareAPI<any>): void,
 }
@@ -55,10 +58,6 @@ export interface EffectsMapObject {
   [key: string]: Effect | EffectWithType,
 }
 
-export interface Dispatch<A extends Action = AnyAction> {
-  <T extends A>(action: T): Promise<any> | T;
-}
-
 export interface SubscriptionAPI {
   history: History,
   dispatch: Dispatch<any>,