Refactor assertion logger to avoid deprecation warnings in Pharo 13

[gcotelli]

No description provided.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.11%. Comparing base (d3fd71e) to head (9ac3387).
⚠️ Report is 1 commits behind head on release-candidate.

Additional details and impacted files

@@                Coverage Diff                 @@
##           release-candidate      #21   +/-   ##
==================================================
  Coverage              99.10%   99.11%           
==================================================
  Files                     11       11           
  Lines                    449      454    +5     
==================================================
+ Hits                     445      450    +5     
  Misses                     4        4           

Flag	Coverage Δ
unit	99.11% <100.00%> (+<0.01%)	⬆️

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