Fix circleci iOS build error

Author: torchhound

.circleci/config.yml

@@ -46,7 +46,7 @@ jobs:
       - run: cd ../hello-react-native && npm install
       - run: sudo npm install -g react-native-cli
       - run: cp -r ../project/ ../hello-react-native/node_modules/launchdarkly-react-native-client-sdk/
-      - run: cd ../hello-react-native && react-native run-ios --configuration Release
+      - run: cd ../hello-react-native && react-native run-ios --configuration Release --simulator rn-ios
 
 workflows:
   version: 2