chore(ci): add PHP 8.5 to CI workflows

[phil-davis]

see if PHP 8.5 works

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.24%. Comparing base (54cc714) to head (4044761).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##             master     #259   +/-   ##
=========================================
  Coverage     94.24%   94.24%           
  Complexity      262      262           
=========================================
  Files            15       15           
  Lines           886      886           
=========================================
  Hits            835      835           
  Misses           51       51           

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[phil-davis]

That works OK. I will leave this to merge after PHP 8.5 is officially released in Nov 2025.

https://wiki.php.net/todo/php85