Move eslint plugin from dependencies to dev dependencies

Summary:
`eslint-plugin-react-native` was a dependencies. I think it should be a dev dependencies like `eslint-plugin-eslint-comments`, `eslint-plugin-flowtype`, `eslint-plugin-jest`, `eslint-plugin-prettier` and `eslint-plugin-react`.

No need

Not needed

[INTERNAL] [ENHANCEMENT] [./package.json] - Move `eslint-plugin-react-native` to devDependencies.
Closes https://github.com/facebook/react-native/pull/18851

Differential Revision: D7991437

Pulled By: hramos

fbshipit-source-id: 5481290423848b9c34df24629086239600d42274

package.json

@@ -159,7 +159,6 @@
     "envinfo": "^3.0.0",
     "errorhandler": "^1.5.0",
     "escape-string-regexp": "^1.0.5",
-    "eslint-plugin-react-native": "^3.2.1",
     "event-target-shim": "^1.0.5",
     "fbjs": "^0.8.14",
     "fbjs-scripts": "^0.8.1",
@@ -213,6 +212,7 @@
     "eslint-plugin-jest": "21.8.0",
     "eslint-plugin-prettier": "2.6.0",
     "eslint-plugin-react": "7.6.1",
+    "eslint-plugin-react-native": "^3.2.1",
     "flow-bin": "^0.72.0",
     "jest": "23.0.0-charlie.1",
     "jest-junit": "3.7.0",