pod 组件验证时报错，Could not find a ios simulator， Ensure that Xcode -> Window -> Devices has at least on
执行 pod lib lint 时，报错：
ERROR | [iOS] unknown: Encountered an unknown error (Could not find a ios simulator (valid values: com.apple.coresimulator.simruntime.ios-10-3, com.apple.coresimulator.simruntime.ios-12-1, com.apple.coresimulator.simruntime.ios-8-1, com.apple.coresimulator.simruntime.tvos-12-1, com.apple.coresimulator.simruntime.watchos-5-1). Ensure that Xcode -> Window -> Devices has at least one ios simulator listed or otherwise add one.
解决办法：
1， 升级CocoaPods（使用的gem 源： https://gems.ruby-china.com/）
sudo gem install cocoapods
再次执行 pod spec lint –verbose –allow-warnings –use-libraries
验证通过
