Release 6.3.0

[AckslD]

Hi! I wanted to update the version used on Nix packages to the latest version in develop branch but maybe it's nice to have that as a proper version. Would it make sense to merge develop into master and tag it with 6.3.0? This would include for example the new commands of clipctl.

[cdown]

Hey! I'm actually about to release a complete rewrite in C which will be tagged as 7.0.0. I've been testing it over the last few days and I think it's more or less ready for external testing, after which it will be released.

[AckslD]

Cool, sounds great :)

[cdown]

The C rewrite is at 70cc5d2 -- feel free to try it out. Packaging shouldn't change much from how it is now, although I might add manual pages.

[AckslD]

Started trying it out @cdown, seems to all work as expected 👍 :)