Fix version on master to 0.13.0-SNAPSHOT
Default branches should always have a patch version of 0, because they are used to build towards new minor releases.
0.13.1-SNAPSHOT will appear in release/0.13
after the tag v0.13.0
is created. That branch is then building towards the first patch of 0.13.
Having artifacts and tags unrelated to those release/0.13
commits can confuse maven, as well as the release candidate logic.
Edited by David Diederich