chore(peerDependencies): allow react@16 to avoid peer dependency warnings

Author: roderickhsiao

package.json

@@ -48,7 +48,7 @@
   },
   "peerDependencies": {
     "@storybook/react": "^3.1.0",
-    "react": "^15.4.0",
+    "react": "^15.4.0 || ^16.0.0",
     "react-intl": "^2.3.0"
   },
   "engines": {