chore(CI): Adjust testing matrix for Nextcloud 28 on stable28

[nickvergessen]

Signed-off-by: Joas Schilling [email protected]

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

:exclamation: No coverage uploaded for pull request base (stable28@a2810f1). Click here to learn what that means.

Additional details and impacted files

@@             Coverage Diff             @@
##             stable28    #1472   +/-   ##
===========================================
  Coverage            ?   44.29%           
  Complexity          ?       99           
===========================================
  Files               ?       19           
  Lines               ?      298           
  Branches            ?        0           
===========================================
  Hits                ?      132           
  Misses              ?      166           
  Partials            ?        0           

Flag	Coverage Δ
unittests	44.29% <0.00%> (?)

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[st3iny]

Superseded by https://github.com/nextcloud/twofactor_totp/pull/1474.