Clarify which repository is the main one

Hello,

I was looking for documentation to build exactly the same kind of widget, thus thank you very much for all your work :)

That said, looking for up-to-date information about this plugin, I find it a bit confusing to understand where the main development occurs now:

• the README refers to a dead link to post issues
• the AUR package advertized in the README use another github repo, on which you cannot post issues, but you can open MR. And this github repo seems to have the newer tags (v0.4.10)
• this gitlab.xfce repository seems to have the most recent commits

Could it be possible to fix the links in the README to better reflect what seems to be a recent move to this xfce gitlab and push missing tags to it?

Thank you very much!