Update flow-bin to the latest version 🚀 (#91)

## The devDependency [flow-bin](https://github.com/flowtype/flow-bin) was updated from `0.88.0` to `0.89.0`.
This version is **not covered** by your **current version range**.

If you don’t accept this pull request, your project will work just like it did before. However, you might be missing out on a bunch of new features, fixes and/or performance improvements from the dependency update.

---

[Find out more about this release](https://github.com/flowtype/flow-bin).

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package.json

@@ -20,7 +20,7 @@
     "conventional-changelog-cli": "^2.0.11",
     "dedent": "^0.7.0",
     "eslint": "^5.6.1",
-    "flow-bin": "^0.88.0",
+    "flow-bin": "^0.93.0",
     "flow-copy-source": "^2.0.2",
     "jest": "^24.1.0",
     "metro-react-native-babel-preset": "^0.49.1",