transmageddon: Require python3-gobject and gtk 3.0

This update fixes the following issues with transmageddon:
- bnc#830725:
+ require GTK 3.0 from the python code. We We know we can't use GTK2, as introspection support is not really given there.
+ Add python3-gobject requirement as transmageddon makes use of gobject-introspection, we need to pull in the python gi loader.

Fixed bugs
bnc#830725
Transmageddon not starting on 12.3
Selected Binaries
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