Detects plugin using old parent pom version

[alecharp]

Description

Plugins are inheriting most of their build configuration through the parent pom (https://github.com/jenkinsci/plugin-pom).
Recent modernization came from it.

It is a good practice to keep the parent pom up to date within any plugin configuration.
Detecting plugin using out of date parent pom could help guide maintainers or new contributors to participate on the project.

[Jagrutiti]

Do I have to compare the version used in the child Pom inside the <parent> tag with this pom: https://github.com/jenkinsci/plugin-pom/blob/master/pom.xml?

In the case of Plugin Health Score, each module has its own pom. These children have a common super pom defined outside the modules.

In this case, do I have to fetch the parent of the pom in each module and compare the version to the pom at https://github.com/jenkinsci/plugin-pom/blob/master/pom.xml?

[AayushSaini101]

Please add GSOC label @alecharp