Version handling on releaseFinish

[fassmus]

When performing releaseFinish the -SNAPSHOT postfix is not striped from version property in gradle.properties before merging the release branch to master. The tag is named correctly but on master we still have the -SNAPSHOT postfix in gradle.properties. On develop the version increment is performed correctly. I also tried to remove the -SNAPSHOT postfix on the release branch before running releaseFinish. This resulted in following error:

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':releaseFinish'.
> didn't replace anything

[RobWin]

Hi, would you like to contribute a PR?

[fassmus]

I will have a go at it next week.