Allow webpack 2 as peerDependency

Author: Einar Löve

packages/react-dev-utils/package.json

@@ -31,6 +31,6 @@
     "strip-ansi": "3.0.1"
   },
   "peerDependencies": {
-    "webpack": "^1.13.2"
+    "webpack": "^1.13.2 || <=2.1.0-beta.25"
   }
 }