style: output cjs files

.gitignore

 node_modules
 coverage
 es/**
+cjs/**

package.json

 {
   "name": "react-keep-alive",
-  "version": "2.0.1",
+  "version": "2.0.2",
   "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",
@@ -17,15 +17,18 @@
   "bugs": {
     "url": "https://github.com/Sam618/react-keep-alive/issues"
   },
-  "main": "es/index.js",
+  "main": "cjs/index.js",
+  "module": "es/index.js",
   "scripts": {
-    "clean": "rimraf es",
+    "clean:es": "rimraf es",
+    "clean:cjs": "rimraf cjs",
     "test": "jest",
     "codecov": "codecov",
     "build:demo": "webpack",
-    "build:es": "npm run clean && tsc",
+    "build:es": "npm run clean:es && tsc",
+    "build:cjs": "npm run clean:cjs && tsc --outDir cjs --module commonjs",
     "start:demo": "webpack-dev-server --hot --historyApiFallback",
-    "start:es": "npm run clean && tsc -w -sourcemap --outDir es"
+    "start:es": "npm run clean:es && tsc -w -sourcemap --outDir es"
   },
   "husky": {
     "hooks": {
@@ -69,6 +72,11 @@
     "webpack-cli": "^3.2.3",
     "webpack-dev-server": "^3.1.14"
   },
+  "peerDependencies": {
+    "react": ">=16.3.0",
+    "react-dom": ">=16.3.0",
+    "react-router-dom": ">=5.0.0"
+  },
   "config": {
     "commitizen": {
       "path": "./node_modules/cz-conventional-changelog"