Bump lodash dependency (#20892)

Summary:
Per [CVE](https://nvd.nist.gov/vuln/detail/CVE-2018-3721) warning.
Pull Request resolved: facebook/react-native#20892

Differential Revision: D9616099

Pulled By: hramos

fbshipit-source-id: 245c09ca32934c5e5464f87bfca213f1b10f8fec

Author: hramos

core/__fixtures__/files/package.json

@@ -50,7 +50,7 @@
     "react-native": ">=0.4.0 || 0.5.0-rc1 || 0.6.0-rc || 0.7.0-rc || 0.7.0-rc.2 || 0.8.0-rc || 0.8.0-rc.2 || 0.9.0-rc || 0.10.0-rc || 0.11.0-rc || 0.12.0-rc || 0.13.0-rc || 0.14.0-rc || 0.15.0-rc || 0.16.0-rc"
   },
   "dependencies": {
-    "lodash": "^3.8.0",
+    "lodash": "^4.17.10",
     "yargs": "^3.30.0",
     "rnpm-plugin-test": "*"
   },