Fix peerDependencies to be compatible with 'prop-types' package (#7)

Author: MichaelDeBoey

package.json

@@ -68,7 +68,7 @@
     "final-form": "^1.0.0",
     "final-form-arrays": "^1.0.0",
     "prop-types": "^15.6.0",
-    "react": "^15.0.0-0 || ^16.0.0-0"
+    "react": "^15.3.0 || ^16.0.0-0"
   },
   "jest": {
     "setupFiles": ["raf/polyfill"]