Add integration tests to check each supported scalac option against each supported scalac version

This is a call-out to trigger a discussion rather than an issue itself.

We could create an IntegrationTest configuration and add tests that would verify whether a certain scalac option is really supported for a specific scalac version.

Checking it by hand is quite boring and unreliable and it would be nice to automate it somehow.
A straightforward solution that comes to mind is using scala-cli for each option and every scala version the project supposed to support:

$ scala-cli compile -S 2.12.12 -O -Xlint:deprecation -- empty.scala
Compiling project (Scala 2.12.12, JVM)
Error: 'deprecation' is not a valid choice for '-Xlint'
Compiled project (Scala 2.12.12, JVM)

whereas

$ scala-cli compile -S 2.12.13 -O -Xlint:deprecation -- empty.scala

compiles without errors.

So would it be possible to employ scala-cli for integration tests in the project and does it look reasonable overall?

See also #5 for a related discussion.

No source file or existing test is named. Start by reviewing the proposed IntegrationTest configuration and the related discussion in #5, then assess how scala-cli could compile an empty.scala example across supported Scala versions and scalac options. Done would mean a decided, project-compatible approach rather than an implementation defined by this issue.