Untranslatable header of "About" window

[TotalCaesar659]

When non-English languages is set, the header of "About" window becomes not translated: I checked and tried to change this, but without a result.

[sharkwouter]

Thanks for reporting this! Honestly, I would expect this to be translatable. The title should be set here and it is a translatable string: https://github.com/sharkwouter/minigalaxy/blob/c7f3736da301813f2ecec39e0be49a00aa660f7b/minigalaxy/ui/about.py#L13

I'm surprised it's not working.