This is a maintenance release.

The change in how shell escaping is handled should not create any BC issues. What used to fail accidentally in potentially unsafe shell situations will now fail deliberately! Note to hosting providers: don't disable escapeshellarg and escapeshellcmd; it's not safe!

• If we can't use escaping functions, refuse to do unsafe things
• Avoid PHP 8.1 trim issue
• Add tests for XMailer
• Fix bug in use of CharSet property
• Fix bug in file upload example
• Update dev dependencies