Add Java outdaten deps check.

[felixhammerl]

As a Java dev
I want to be notified about outdated dependencies
So that I can ingest fix-forward solutions.

Description

Same as Node and Python, Java should have a means to understand which libraries are outdated. Libraries are used in a fix-forward manner, hence comsuming them for the build could have a beneficial impact on the ecosystem.

Acceptance Criteria

• I get alerted to outdated software
• There are no additional libraries you have got to install to get top running

Unresolved Questions

• What tools out there are freely available?
• What tools are applicable this task?

[csokol]

It seems like for maven projects, there's a maven official plugin that shows outdated dependencies: https://www.mojohaus.org/versions-maven-plugin/display-dependency-updates-mojo.html

We could run that from the scanner and parse the output to find out outdated libs.

For gradle and sbt, there's no official plugins. There unofficial ones but it'd require that the user configure them in the build.sbt or build.gradle which doesn't look like a good idea.

Do you think it's worth adding this feature at least for maven projects for now?