react-native: add iPhone XR, XS, and XS Max simulators (#7145)

plugins/react-native/react-native.plugin.zsh

@@ -15,6 +15,9 @@ alias rnios8='react-native run-ios --simulator "iPhone 8"'
 alias rnios8p='react-native run-ios --simulator "iPhone 8 Plus"'
 alias rniosse='react-native run-ios --simulator "iPhone SE"'
 alias rniosx='react-native run-ios --simulator "iPhone X"'
+alias rniosxs='react-native run-ios --simulator "iPhone XS"'
+alias rniosxsm='react-native run-ios --simulator "iPhone XS Max"'
+alias rniosxr='react-native run-ios --simulator "iPhone XR"'
 
 alias rnland='react-native log-android'
 alias rnlios='react-native log-ios'