PHPUnit extension for reporting test warnings in PhpStorm

Rationale: with current PHPUnit versions, only critical failures that change the outcome of a test are visible in PhpStorm's testing UI and cause the test to be considered failed. This can lead to confusion and wasted developer time, e.g. when the tests are green in PhpStorm but fail in CI. This extension modifies PHPUnit's logging mechanism so that non-critical issues are also reported and cause a test failure in PhpStorm: pawel-slowik/phpunit-phpstorm-issue-logging.

Related PHPUnit issue: failOnWarning="true" but tests with warnings marked as passed in PHPStorm.

Related JetBrains issues:

• PhpStorm considers the phpunit tests as passed even though there is a warning
• PHPUnit wrong exit code handling

Hope this saves someone some headaches during debugging :)