docs: document version support goals

[codecov[bot]]

Codecov Report

Merging #424 into master will not change coverage by %. The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #424   +/-   ##
=======================================
  Coverage   97.99%   97.99%           
=======================================
  Files           2        2           
  Lines         449      449           
  Branches       39       36    -3     
=======================================
  Hits          440      440           
  Misses          9        9           

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