Abandon myget feed

[UlyssesWu]

I do appreciate myget for hosting my packages for free.
Most of time it's easy to use (without need of YAML configs), with one click you can build and push a package to feed.
However, myget has been inactive for a long time:
The build service still lacks many config options and cannot build .NET 6+ projects.
The website is slow and not friendly for Edge browser.
Perhaps they just cannot make enough money for living. That's a sad story.

I think I have to move to another package feed service, better without YAML configs🤔
When it's done, devs who are using FreeMote as submodules will have to update, so I post this issue in advance.