Add 2.0.0 language version compatibility to detekt-compiler-plugin

[3flex]

Expected Behavior

detekt-compiler-plugin supports the same language versions as Kotlin itself.

Current Behavior

It does not work with language version 2.0 and up.

Context

Users will either be held back from upgrading to new Kotlin versions or will have to switch away from the compiler plugin.

Also see #7303 - ./gradlew detekt-compiler-plugin:test should work with this PR reverted.