Add CODEOWNERS file to make it more apparent who the owner(s) is/are of this repo

[Drew-Daniels]

GitHub has a feature called Code Owners that can make it easier to determine who owns a given repo.

I wasn't sure if this repo was still maintained, because there seem to be lots of issues around jest tests not being detected by this plugin, and I think adding something like this might help make it more apparent who people need to reach out to if there isn't movement on certain things.

[danielwikander]

I agree. For example:
There was a PR yesterday that seems to fix a lot of issues people have been having (#104) but it's unclear if this repo has any active maintainers that will look at it.