ERROR during build of m-plugin-report-p and m-plugin-p: Dependencies in wrong scope

The following errors can be observed during the build of the current master since MPLUGIN-441

[INFO] --- maven-plugin-plugin:3.6.4:descriptor (default-descriptor) @ maven-plugin-plugin ---
[ERROR] 

Some dependencies of Maven Plugins are expected to be in provided scope.
Please make sure that dependencies listed below declared in POM
have set '<scope>provided</scope>' as well.

The following dependencies are in wrong scope:
 * org.apache.maven:plexus-utils:jar:4.0.0-alpha-2:compile

[INFO] Using 'UTF-8' encoding to read mojo source files.
[INFO] java-annotations mojo extractor found 5 mojo descriptors.

This is emitted 4 times (for both goals descriptor and help-mojo in modules m-plugin-report-p and m-plugin-p).

In addition plexus-utils is now twice in the dependency hierarchy:

• Directly referenced with group id o.a.m
• Transitively referenced with group id org.codehaus.plexus, e.g. from maven-core.

As they cannot really coexist in the same classloader (as both export at least partially the same package names) only one version should ever be used....