UPM support

[starikcetin]

Can we introduce UPM support to be used with https://github.com/mob-sakai/UpmGitExtension? I can do that for you if you don't have time.

[starikcetin]

I made it. It is working: https://github.com/starikcetin/UniRx

If you give me an orphan branch named upm I can send a pull request.

@neuecc

[FreakTheMighty]

@starikcetin how does a release work? Is it an automated flow, or are you branching then moving files manually?

[starikcetin]

There is no releasing. The system tracks git refs. So when you make a UPM branch and make a commit there, it is basically a new release - that being said, you can simulate release cycles with semver compatible git tags.

For organizing the files, there is no need for copy-paste or moving stuff around. Take a look here: https://github.com/starikcetin/awesome-upm#how-to-support-upm-in-my-git-repository

@FreakTheMighty

[MartinGonzalez]

Please merge!

[shiena]

You can use path query parameter from unity2019.3.4f1 and unity2020.1a21.
https://forum.unity.com/threads/some-feedback-on-package-manager-git-support.743345/#post-5425311