2.2.0: PHP 8.5, E_STRICT deprecation

• Added PHP 8.5 to the test matrix, ensuring forward compatibility
  (@thekid)
• Removed deprecated E_STRICT mapping from warnings. See these RFCs:
  • https://wiki.php.net/rfc/reclassify_e_strict (7.0)
  • https://wiki.php.net/rfc/deprecations_php_8_4 (8.4)
    (@thekid)