Turn off operator-assignment stylistic rule (facebook#2256)

Author: gaearon

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

@@ -210,7 +210,6 @@ module.exports = {
     ],
     'no-with': 'warn',
     'no-whitespace-before-property': 'warn',
-    'operator-assignment': ['warn', 'always'],
     radix: 'warn',
     'require-yield': 'warn',
     'rest-spread-spacing': ['warn', 'never'],