style: fix KeepAlive.tsx and useKeepAliveEffect.tsx TSLint Error

package.json

 {
   "name": "react-keep-alive",
-  "version": "2.0.0.alpha.0",
+  "version": "2.0.0-alpha.0",
   "description": "Package will allow components to maintain their status, to avoid repeated re-rendering.",
   "author": "Shen Chang",
   "homepage": "https://github.com/Sam618/react-keep-alive",

src/components/KeepAlive.tsx

@@ -25,9 +25,9 @@ class KeepAlive extends React.PureComponent<IKeepAliveInnerProps> {
 
   private ref: null | Element = null;
 
-  private refNextSibling: null | ChildNode = null;
+  private refNextSibling: null | Node = null;
 
-  private childNodes: ChildNode[] = [];
+  private childNodes: Node[] = [];
 
   public componentDidMount() {
     const {

src/utils/useKeepAliveEffect.tsx

-import React, {useEffect, useContext, useRef, useState} from 'react';
+import React, {useEffect, useContext, useRef} from 'react';
 import {warn} from './debug';
 import {COMMAND} from './keepAliveDecorator';
 import IdentificationContext, {IIdentificationContextProps} from '../contexts/IdentificationContext';