Run PHPUnit on other versions of MW

[malberts]

PHPUnit was running only for MW REL1_36 due to this PHP version check.

Everything passes. I assume the original check was due to PHP 8.1 compatibility issues 2 years ago.

[codecov-commenter]

Codecov Report

Merging #29 (89d4ae9) into master (dc54bf9) will not change coverage. The diff coverage is n/a.

:exclamation: Current head 89d4ae9 differs from pull request most recent head 8b76fc8. Consider uploading reports for the commit 8b76fc8 to get more accurate results

@@            Coverage Diff            @@
##             master      #29   +/-   ##
=========================================
  Coverage     98.25%   98.25%           
  Complexity      112      112           
=========================================
  Files            20       20           
  Lines           286      286           
=========================================
  Hits            281      281           
  Misses            5        5