[FR] add support for gitlab and other platforms #1
Description
The original appimageupdate only has support for gh-releases-zsync, which makes it search for the latest zsync release on github with this format:
gh-releases-zsync|<username>|<repo>|<tag>|<filename> (with filename supporting simple globbing).
For other platforms, people instead have to use zsync|<url> which is very problematic, because it has to be a fixed url that projects have to setup.
Would be great to also have gl-releases-zsync for gitlab, cb-releases-zsync for codeberg and so on. Which would do what gh-releases-zsync does but on those platforms.