update ios buildNumber to 0.2.0 in app.json

app.json

@@ -24,7 +24,7 @@
     "ios": {
       "bundleIdentifier": "com.clicknpush.app",
       "googleServicesFile": "./GoogleService-Info.plist",
-      "buildNumber": "0.1.15"
+      "buildNumber": "0.2.0"
     },
     "android": {
       "googleServicesFile": "./google-services.json",