fix(deps): update dependency checkstyle to v10.21.0

[renovate]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
checkstyle (source)	10.20.2 -> 10.21.0

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Release Notes

checkstyle/checkstyle (checkstyle)

v10.21.0

Compare Source

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Configuration

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.08%. Comparing base (b32f644) to head (a3963a9).
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #6951   +/-   ##
=========================================
  Coverage     90.08%   90.08%           
  Complexity     6600     6600           
=========================================
  Files           730      730           
  Lines         19843    19843           
  Branches       1955     1955           
=========================================
  Hits          17876    17876           
  Misses         1371     1371           
  Partials        596      596           

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