Update mysql Docker tag to v8.4

[renovate]

This PR contains the following updates:

Package	Update	Change
mysql	minor	8.3 -> 8.4

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 62.06%. Comparing base (4c5bb90) to head (a6cd4f5).
Report is 10 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #309      +/-   ##
==========================================
- Coverage   66.05%   62.06%   -3.99%     
==========================================
  Files           4        4              
  Lines         436      464      +28     
==========================================
  Hits          288      288              
- Misses        140      168      +28     
  Partials        8        8              

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