build: auto-prepare before releasing

I'm sure I will forget the prepare step in the future, so instead
I'm bundling it into the release so I cannot forget it.

Author: thehale

package.json

@@ -43,7 +43,7 @@
     "lint": "eslint \"**/*.{js,ts,tsx}\"",
     "clean": "del-cli android/build example/android/build example/android/app/build example/ios/build lib",
     "prepare": "bob build",
-    "release": "release-it"
+    "release": "yarn prepare && release-it"
   },
   "keywords": [
     "react-native",