Allow run-ios to accept an xcconfig to be used in xcodebuild

Describe the Feature

I would love to see the ability to pass in an xcconfig file to run-ios so that configs can be used to customize the build process with xcodebuild. This is a very important feature for whitelabeled applications that use xcconfig, scheme and configuration for different versions of an app. I was able to make a 2 line change to pass in the xcconfig locally and it worked without issue.

Possible Implementations

File https://github.com/react-native-community/cli/blob/master/packages/platform-ios/src/commands/runIOS/index.ts#L570 Change Add a new option Implementation

{
  name: '--xcconfig [string]',
  description: 'Explicitly set xcconfig to use',
}

File https://github.com/react-native-community/cli/blob/master/packages/platform-ios/src/commands/runIOS/index.ts#L414 Change Pass xcconfig to xcodebuildArgs Implementation

const xcodebuildArgs = [
  xcodeProject.isWorkspace ? '-workspace' : '-project',
  xcodeProject.name,
  ... args.xcconfig ? ['-xcconfig', args.xcconfig] : [],
  '-configuration',
  args.configuration,
  '-scheme',
  scheme,
  '-destination',
  `id=${udid}`,
];

Related Issues

N/A

[ShaswatPrabhat]

PR for the issue

[ShaswatPrabhat]

Will share a PR for the same ASAP