chore(package): update flow-bin to version 0.57.2

Closes #34

Author: greenkeeper[bot]

package.json

@@ -66,7 +66,7 @@
     "eslint": "^4.1.0",
     "eslint-plugin-flowtype": "^2.30.4",
     "eslint-watch": "^3.1.0",
-    "flow-bin": "^0.56.0",
+    "flow-bin": "^0.57.2",
     "flow-watch": "^1.1.1",
     "istanbul": "^0.4.5",
     "mocha": "^3.5.3",