Gather test coverage data for danger-swift

Reading the Swift 5 release notes for Xcode 10.2 beta, it sounds like SPM projects will be able to gather test coverage data via the command line (my understanding is that it is not possible in current versions of Swift):

> The swift test command can generate code coverage data in a standard format suitable for consumption by other code coverage tools using the flag --enable-code-coverage. The generated code coverage data is available inside build-dir/configuration/codecov.

https://developer.apple.com/documentation/xcode_release_notes/xcode_10_2_beta_release_notes/swift_5_release_notes_for_xcode_10_2_beta

I would like to make a Danger-Swift plugin to grab this coverage data and then use this to comment coverage info for each PR in this repo. (I hope "standard format suitable for consumption by other code coverage tools" means JSON.)

Sound good?