[maint]: add release process & release new version

[vladdoster]

Summary

Discussed in https://github.com/zdharma-continuum/zinit/discussions/344

^{Originally posted by FranklinYu July 15, 2022} Last tag (v3.7) was cut in December 2020; since then, there has been 446 commits in the main branch: https://github.com/zdharma-continuum/zinit/compare/v3.7...main

Is it worth cutting a new release? There isn’t anything I’m waiting for so far, but that’s probably because I’m new here.

Proposed fix

Do the needful