Update release process docs to include tag vX.Y.0-dev on master branch

[lafriks]

Update release process documentation

[codecov-io]

Codecov Report

Merging #5091 into master will decrease coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master   #5091      +/-   ##
=========================================
- Coverage   37.41%   37.4%   -0.02%     
=========================================
  Files         306     306              
  Lines       45374   45374              
=========================================
- Hits        16978   16973       -5     
- Misses      25944   25947       +3     
- Partials     2452    2454       +2

Impacted Files	Coverage Δ
models/repo_indexer.go	50.84% <0%> (-1.28%)	⬇️
models/repo_list.go	61.76% <0%> (-1.18%)	⬇️

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