Pinta now uses dotnet 6.0 + GTK3 instead of old mono + gtk-sharp (GTK2)
library. So build it with the new buildDotnetModule introduced sometime ago.
This does causes some small issues. For example, there is no translations
since this is build using autoreconf + intltool + pkg-config. There is no
way to build just translations using this build system AFAIK. Shouldn't be
too much of an issue considering that we also didn't had translations
before (or it was incomplete).