Bump Jest version (facebook#1432)

Author: gaearon

packages/react-scripts/package.json

@@ -51,7 +51,7 @@
     "gzip-size": "3.0.0",
     "html-webpack-plugin": "2.24.0",
     "http-proxy-middleware": "0.17.2",
-    "jest": "18.0.0",
+    "jest": "18.1.0",
     "json-loader": "0.5.4",
     "object-assign": "4.1.0",
     "postcss-loader": "1.0.0",