RANGER-5688: maven-source-plugin.version property is referenced but never defined

[magnuma3]

What changes were proposed in this pull request?

RANGER-4076 replaced the hardcoded maven-source-plugin version in the root pom's pluginManagement with a property reference, but the property was never defined:

<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-source-plugin</artifactId>
<version>${maven-source-plugin.version}</version>

git grep '<maven-source-plugin.version>' returns nothing.

Since pluginManagement entries are only resolved when the plugin is actually invoked, normal builds are unaffected. But any invocation of the plugin by prefix, e.g.:

mvn install source:jar -DskipTests -Denunciate.disable.sourcepath=true

fails at startup, because the undefined property survives as a literal and Maven tries to resolve version ${maven-source-plugin.version} from central:

[ERROR] Plugin org.apache.maven.plugins:maven-source-plugin:${maven-source-plugin.version} or one of its dependencies could not be resolved

Fix: define the property alongside the other plugin versions in the root pom, e.g. <maven-source-plugin.version>3.3.1</maven-source-plugin.version>.

How was this patch tested?

(Please explain how this patch was tested. Ex: unit tests, manual tests)
(If this patch involves UI changes, please attach a screen-shot; otherwise, remove this)