update minimum Maven version to 3.1.0

[elharo]

@ian-lavallee @rfscholte I can update the minimum Maven version here to 3.1.0, but to do this I have to dd maven-compat back in, at least for tests. Can anyone see how I might do this without maven-compat? When I try I tend to get errors like

WARNING: Error injecting: org.apache.maven.repository.legacy.LegacyRepositorySystem
java.lang.NoClassDefFoundError: org/sonatype/aether/RepositorySystemSession

That is, something is still asking for Sonatype Aether. It's not immediately obvious to me where/how the binding for RepositorySystemSession is set.

[rfscholte]

Having maven-compat for test is likely required when it is using maven-plugin-testing-harness. And this one is probably respnsible for pulling in Sonatype Aether. A quick look tells me the testing-harness should be upgraded to 3.1.0 to be Maven 3.1.0 compatible. I'll add it to https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=155749857

[ian-lavallee]

Not sure. When I was making the custom verbose tree plugin I needed to add compat when using the maven-plugin-testing-harness too.

[elharo]

Caused by: org.apache.maven.plugin.PluginContainerException: An API incompatibility was encountered while executing org.apache.maven.plugins:maven-dependency-plugin:3.1.3-SNAPSHOT:analyze: java.lang.IncompatibleClassChangeError: class org.apache.maven.shared.dependency.analyzer.asm.DefaultAnnotationVisitor has interface org.objectweb.asm.AnnotationVisitor as super class

[elharo]

Tentatively issue is that maven-compat pulls in an old version of asm:asm instead of org.ow2.asm:asm so both end up in the classpath.