Add react and react-dom as peer dependencies (#253)

Author: yoyo837

package.json

@@ -45,7 +45,8 @@
     "now-build": "npm run docs:build"
   },
   "peerDependencies": {
-    "react": ">= 16.9.0"
+    "react": ">= 16.9.0",
+    "react-dom": ">= 16.9.0"
   },
   "dependencies": {
     "@babel/runtime": "^7.8.4",