chore(package): update flow-bin to version 0.50.0

Author: greenkeeper[bot]

package.json

@@ -39,7 +39,7 @@
     "eslint-plugin-flowtype": "^2.34.0",
     "eslint-plugin-import": "^2.3.0",
     "eslint-plugin-prettier": "^2.1.1",
-    "flow-bin": "^0.49.1",
+    "flow-bin": "^0.50.0",
     "graphql": "^0.10.1",
     "graphql-compose": "^2.0.0",
     "jest": "^20.0.4",