I think this really depends on your target audience, and the license model under which your application is developed (i.e open source or closed source). I know your question mentions who your target audience is in this particular case, but in order to provide an answer that is useful to everyone I think this is best ignored for answers.
As a developer you want to be getting as much feedback as possible for issues and bugs, and the easier you make it for users, the more likely they are to do so.
Providing an email address, or as mentioned by Florian Margaine, a contact form, is probably the best option. This will result in far more feedback from users, and will make it far more likely that bugs are reported. As you can imagine though, you will receive multiple reports for each bug - this is both a positive and a negative. On the one hand it will result in a lot of duplication of issues, but this can be a positive in that it lets you see just how many users are encountering the issue, and you can the prioritise it accordingly.
Providing a link to github or any other bug tracking system may confuse the average user, so if your product is going to be used by inexperienced users, then this may be best avoided. If you must direct them to such a system, then make sure they can submit a bug report by entering as few details as possible - just a title and description is all you really need, anything else can be added later.
If your product is going to be open source, however, then there is an added bonus that by linking to github or similar, not only can users report bugs, but see what bugs are being reported and fix them themselves.
So for an open source product or a product that targets a highly technical user base, then linking to github may be the best bet, but for your average user, an email address or contact form may suffice.
However, there is no reason that you cannot do both, thereby letting the user choose which system they find is most suitable to their abilities.