Fix scalaCompatVersion check, closes #732

[jozic]

@slandelle per discussion in #732, here's a PR with a test

[davidB]

Thank you for the targeted fix and the test.

We still miss a test when the warning should be raised, and to think if it's relevant to keep this "feature" or to remove it.

[jozic]

Hey @davidB, thanks for checking it out!
in fact such a test exists in https://github.com/davidB/scala-maven-plugin/tree/master/src/it/mismatchedScalaVersions
i just coped it and modified to make sure we don't have the warning when compat version is set and scala versions are compatible

or do you talk about some other test?

[jozic]

@slandelle do you mind checking this quickly? it's pretty small )

[LeRiton]

Hi everyone,
Thanks @jozic for the patch!
Any plan to merge this for the next release?