WARN if generated plugin.xml contains <requirement>

[hboutemy]

New feature, improvement proposal

we deprecated @Component for some time now https://issues.apache.org/jira/browse/MPLUGIN-530

with recent issue discovered apache/maven#12555, it can be useful to get one step further and get a WARN hint when a plugin descriptor is written with a <requirement>, as currently, there is no message:

[INFO] --- plugin:3.15.2:descriptor (default-descriptor) @ cyclonedx-maven-plugin ---
[INFO] Using 'UTF-8' encoding to read mojo source files.
[INFO] java-annotations mojo extractor found 3 mojo descriptors.
[INFO] java-javadoc mojo extractor found 0 mojo descriptor.
[INFO] ant mojo extractor found 0 mojo descriptor.
[INFO] bsh mojo extractor found 0 mojo descriptor.

[slawekjaranowski]

for reference:

• Add validation for Plexus-based plugin dependency injection maven#12577