From my understanding, it is not possible for a program depending on Wiki.java (such as Pattypan) to be released under the MIT license. The GPL is viral, meaning that its terms require that it also applies to derivatives.
Possible mitigations:
Change Pattypan to GPLv3+
Convince the authors of Wiki.java to switch to a permissive license such as MIT or LGPL (which I think would work too)
The Wiki.java library is released mostly under GPLv3+, with some parts in AGPLv3+.
From my understanding, it is not possible for a program depending on Wiki.java (such as Pattypan) to be released under the MIT license. The GPL is viral, meaning that its terms require that it also applies to derivatives.
Possible mitigations: