Maven/Java versions coverage

[wlargou]

Suggest to support more maven and java version for the build (as older projects fail with this builder)

Describe the Enhancement

Add the ability to specify specific maven / java version to use for the build

Possible Solution

Need contribution guidelines as part of docs (or I couldn't find it)

Motivation

Greater adoption

[dmikusa]

The support we provide is for the latest versions of each Java long-term support release (8, 11, 17, 21) and the latest version of the non-LTS release, presently 22. We support the latest version of stable Maven, 3, and latest version of the preview of Maven 4.

You can pin to older versions of the buildpack if you must stay on a non-supported version, but we strongly recommend keeping up with the latest releases of the major branch that you're running so that you get all of the security and bug fixes in those releases.

Users of Maven and Gradle are also strongly recommended to use the Maven or Gradle wrapper, which is supported by the buildpack. When you do this, the buildpack will allow the wrapper to install your selected version of Maven or Gradle so you can have more fine-grained control.