Flowable 6.1.2 release

Bug fix release:

Thanks to whee we found out that there's an issue with the release 6.1.1 when running it without an Internet connection https://forum.flowable.org/t/upgrading-6-1-0-to-6-1-1-could-not-read-idm-mybatis-configuration-file/753. This was fixed with the following commit 7338015. Although an Internet connection is often available, we decided to do a bug fix release to prevent people from running into this issue.