Drop support for Scala 2.10/2.11, bump version to 2.0.0-SNAPSHOT

[jozic]

Drop Scala 2.10 and 2.11 and simplify artifacts resolution.
This works for some tests in https://github.com/scoverage/scoverage-maven-samples (those that use scala-maven-plugin, scalatest or surefire and Scala 2.12/2.13; specs2 maven plugin doesn't support latest spec2, sbt-compiler-maven-plugin tests fail on master)

[jozic]

@ckipp01 do you mind checking this out?

[ckipp01]

I'm totally fine with this approach. Just keep in mind that we will have to add some logic back in here to support Scala 3 since not all the artefacts are needed in that case -- since the compiler emits coverage date natively.

Thanks again for continuing to work on this @jozic .

[jozic]

Thanks for review @ckipp01!
As of now Scala 3 is not "supported" and an attempt to use master branch code with Scala 3 will result in Skipping SCoverage execution - unsupported Scala version, so I do understand that for Scala 3 support we need to do more.
Which I would like to do after we release new version of the plugin.