Pre-release version bump 0.6.0
Pre-release version bump 0.6.0

davidmalcolm/pygobject,davidmalcolm/pygobject,choeger/pygobject-cmake,alexef/pygobject,GNOME/pygobject,Distrotech/pygobject,davibe/pygobject,thiblahute/pygobject,jdahlin/pygobject,Distrotech/pygobject,choeger/pygobject-cmake,pexip/pygobject,thiblahute/pygobject,jdahlin/pygobject,MathieuDuponchelle/pygobject,davidmalcolm/pygobject,GNOME/pygobject,nzjrs/pygobject,sfeltman/pygobject,nzjrs/pygobject,pexip/pygobject,GNOME/pygobject,nzjrs/pygobject,Distrotech/pygobject,MathieuDuponchelle/pygobject,alexef/pygobject,sfeltman/pygobject,davibe/pygobject,davibe/pygobject,alexef/pygobject,davibe/pygobject,jdahlin/pygobject,thiblahute/pygobject,Distrotech/pygobject,sfeltman/pygobject,choeger/pygobject-cmake,MathieuDuponchelle/pygobject,pexip/pygobject