FR: Gradle & SBT projects should get tested...

[lesv]

It doesn't appear that either .sbt or build.gradle projects are being tested. They should be. Now that we have the btlr tool, it should be easy to add the code.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.