Upgrade to lodash@^4.16.6

Summary:
This diff updates `lodash` so that it's optimally deduped, resulting in:

* reducing the packager's load time by ~300-400ms.
* reduces the size of `node_modules` from ~225MB to ~148MB.
* reduces the time to do a clean `yarn install` from 35s to 18s.

Lots of dependencies (including every `babel-*`) use `lodash@4`, by having `lodash@3` as a root dependency, each package had to have it's own copy of `lodash@4`. Now, there's only one.

The uses of `lodash` in RN are restricted to the CLI/packager, and the uses are pretty basic. The breaking APIs don't really seem to affect us https://github.com/lodash/lodash/wiki/Changelog#v400.

Reviewed By: bestander

Differential Revision: D4124836

fbshipit-source-id: 0849c385fcafe10b463e684fea47be6775982386

package.json

@@ -174,7 +174,7 @@
     "json-stable-stringify": "^1.0.1",
     "json5": "^0.4.0",
     "jstransform": "^11.0.3",
-    "lodash": "^3.10.1",
+    "lodash": "^4.16.6",
     "mime": "^1.3.4",
     "mime-types": "2.1.11",
     "minimist": "^1.2.0",