chore(package): update eslint-plugin-flowtype to version 5.0.2

Closes #291

Author: greenkeeper[bot]

package.json

@@ -71,7 +71,7 @@
     "del-cli": "^1.1.0",
     "eslint": "^4.19.0",
     "eslint-config-airbnb-base": "^12.1.0",
-    "eslint-plugin-flowtype": "^2.29.1",
+    "eslint-plugin-flowtype": "^5.0.2",
     "eslint-plugin-flowtype-errors": "^3.5.1",
     "eslint-plugin-import": "^2.9.0",
     "fast-async": "^6.1.2",