Tweak 'specific' update heuristic

[fthomas]

This selects the replaceVersion implementation based on the specific update.

[codecov]

Codecov Report

Merging #2125 (ae267b3) into master (9b11752) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #2125   +/-   ##
=======================================
  Coverage   78.16%   78.16%           
=======================================
  Files         131      131           
  Lines        2249     2249           
  Branches       50       57    +7     
=======================================
  Hits         1758     1758           
  Misses        491      491           

Impacted Files	Coverage Δ
...a/org/scalasteward/core/edit/UpdateHeuristic.scala	98.80% <100.00%> (-0.02%)	⬇️
...scala/org/scalasteward/core/scalafmt/package.scala	100.00% <100.00%> (ø)

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