Document required min Maven version

[eva-mueller-coremedia]

Describe your use-case which is not covered by existing documentation.

Documentation

Highlight to use at least Maven 3.9.6 when developing this plugin.

Background

With the new parent

<parent>
  <groupId>org.jenkins-ci.plugins</groupId>
  <artifactId>plugin</artifactId>
  <version>5.3</version>
  <relativePath />
</parent>

Maven 3.9.6 is required

If you build with Maven < 3.9.6, you will get the following cryptic error:

Unknown packaging: hpi @ org.jenkins-ci.plugins:PLUGIN:${revision}.${changelist}, /pom.xml, line 13, column 14

[ERROR] [ERROR] Some problems were encountered while processing the POMs:
[ERROR] Unknown packaging: hpi @ org.jenkins-ci.plugins:PLUGIN:${revision}.${changelist}, <PATH_TO_POM>/pom.xml, line 13, column 14
 @ 
[ERROR] The build could not read 1 project -> [Help 1]
org.apache.maven.project.ProjectBuildingException: Some problems were encountered while processing the POMs:
[ERROR] Unknown packaging: hpi @ org.jenkins-ci.plugins:PLUGIN:${revision}.${changelist}, <PATH_TO_POM>/pom.xml, line 13, column 14

    at org.apache.maven.project.DefaultProjectBuilder.build (DefaultProjectBuilder.java:389)
    at org.apache.maven.graph.DefaultGraphBuilder.collectProjects (DefaultGraphBuilder.java:349)
    at org.apache.maven.graph.DefaultGraphBuilder.getProjectsForMavenReactor (DefaultGraphBuilder.java:340)
    at org.apache.maven.graph.DefaultGraphBuilder.build (DefaultGraphBuilder.java:76)
    at org.apache.maven.DefaultMaven.buildGraph (DefaultMaven.java:448)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:197)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:173)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:101)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:827)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:272)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:195)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:77)
    at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke (Method.java:568)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)
[ERROR]   
[ERROR]   The project org.jenkins-ci.plugins:PLUGIN:4.999999-SNAPSHOT (<PATH_TO_POM>/pom.xml) has 1 error
[ERROR]     Unknown packaging: hpi @ org.jenkins-ci.plugins:PLUGIN:${revision}.${changelist}, <PATH_TO_POM>/pom.xml, line 13, column 14
[ERROR] 
[ERROR] 

<PATH_TO_POM>/pom.xml, line 13, column 14 is <packaging>hpi</packaging>.

Source Code

I then had a look at the source code and saw

• https://github.com/jenkinsci/maven-hpi-plugin/blob/master/pom.xml#L27 explicitly requires Maven 3.9.6.
• Maven 3.9.6 is also defined in https://github.com/jenkinsci/plugin-pom/blob/master/pom.xml#L518.

Reference any relevant documentation, other materials or issues/pull requests that can be used for inspiration.

No response

Are you interested in contributing to the documentation?

No response

[programbeginnerTW]

@eva-mueller-coremedia, I've added the Maven version notice inside /docs/CONTRIBUTING.md.
Here's the PR link: PR#514