Update yoast/phpunit-polyfills requirement from ^2.0 to ^4.0#2

PDowney merged 1 commit intomainEngineScript/simple-wp-optimizer:mainfrom

dependabot/composer/yoast/phpunit-polyfills-tw-4.0EngineScript/simple-wp-optimizer:dependabot/composer/yoast/phpunit-polyfills-tw-4.0Copy head branch name to clipboard