test: migrate to phpunit 11

[phil-davis]

convert test annotations to PHP attributes

The XML schema is the same for PHPunit 10 and 11,
so that does not need to be migrated.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.98%. Comparing base (4d71e5b) to head (893a10a).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##             master     #282   +/-   ##
=========================================
  Coverage     93.98%   93.98%           
  Complexity      263      263           
=========================================
  Files            15       15           
  Lines           864      864           
=========================================
  Hits            812      812           
  Misses           52       52           

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