Add tjkuson as a maintainer

[seifertm]

The PR also removes @Tinche and @asvetlov from CODEOWNERS. Please let me know by the end of the week, if you want to be kept in CODEOWNERS, so I can revert the change.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.50%. Comparing base (1975f90) to head (d70416e).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1515   +/-   ##
=======================================
  Coverage   94.50%   94.50%           
=======================================
  Files           2        2           
  Lines         510      510           
  Branches       62       62           
=======================================
  Hits          482      482           
  Misses         22       22           
  Partials        6        6           

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