You can report issues here https://github.com/mendix/CommunityCommons/issues
You can create a pull request, if you forked the repository, with your additions/ fixes and we will take care of the versioning.
We've added some basic information about GitHub in combination with Mendix here: https://world.mendix.com/display/howto50/Contributing+to+a+GitHub+repository
Please let us know, in this question for example, if you find anything we can improve regarding this documentation. Thanks!