Update GermaNet API to support GermaNet 15

[matlaj]

The package de.tudarmstadt.ukp.dkpro.lexsemresource.germanet-gpl should be updated to use a more recent version of the GermaNet API, as the current one does not support the most recent GermaNet dataset.

I've been testing version 13.2.1 on my own machine, and there is just one minor incompatibility -- but it's unclear to me whether the change that's responsible is intentional or not (hopefully we get an answere here). I'm also unsure what would be the best way to handle the situation in LSR, so I think for now version 13.1.0 would be sufficient. This version also supports the current GermaNet data, and there is no incompatibility.