Jitpack.io: Support Maven wrapper

[bsideup]

Hi!

There is Maven wrapper project similar to Gradle wrapper:
https://github.com/takari/maven-wrapper

Would be great if JitPack will support it to allow users to control Maven version

[KostyaSha]

Guys, specifying maven version is critical because maven 3.3 has regressions in reactor ordering during shading operations. Also i want run the same maven version that i tested locally and don't have accidental updates in build system.

[jitpack-io]

Added! If there's a ./mvnw script in the repository then JitPack will use that instead of mvn.

[bsideup]

@jitpack-io this is great! Thank you!

[KostyaSha]

Thank you!