Re-enable flowtype warning (#2718)

* Re-enable flowtype warning

* Update eslint-plugin-flowtype dependency

Author: Oskar Köök

packages/eslint-config-react-app/index.js

@@ -291,8 +291,7 @@ module.exports = {
 
     // https://github.com/gajus/eslint-plugin-flowtype
     'flowtype/define-flow-type': 'warn',
-    // TODO: Reenable once https://github.com/gajus/eslint-plugin-flowtype/issues/165 is fixed
-    //'flowtype/require-valid-file-annotation': 'warn',
+    'flowtype/require-valid-file-annotation': 'warn',
     'flowtype/use-flow-type': 'warn',
   },
 };

packages/eslint-config-react-app/package.json

@@ -13,7 +13,7 @@
   "peerDependencies": {
     "babel-eslint": "^7.2.3",
     "eslint": "^4.1.1",
-    "eslint-plugin-flowtype": "^2.33.0",
+    "eslint-plugin-flowtype": "^2.34.1",
     "eslint-plugin-import": "^2.2.0",
     "eslint-plugin-jsx-a11y": "^5.0.3",
     "eslint-plugin-react": "^7.0.1"