update release procedure

[gammazero]

Update release procedures to not use the release branch. Instead, create separate release-vX.Y.Z branch that merges directly into main.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 60.50%. Comparing base (17db35a) to head (20e4b0c).
Report is 22 commits behind head on main.

@@            Coverage Diff             @@
##             main     #773      +/-   ##
==========================================
- Coverage   60.55%   60.50%   -0.06%     
==========================================
  Files         245      245              
  Lines       31126    31126              
==========================================
- Hits        18848    18832      -16     
- Misses      10607    10620      +13     
- Partials     1671     1674       +3     

see 12 files with indirect coverage changes