More Units and some maintenance

Added

• Added Target unit (#38) (thanks to @peter279k)
• Added Swap unit (#39) (thanks to @peter279k)
• Added Automount unit (#40) (thanks to @peter279k)
• Added Mount unit (#41) (thanks to @peter279k)

Changed

• Replace Travis CI with GitHub Action status badge (#44) (thanks to @peter279k)
• Migrate phpunit.xml for new version (#42) (thanks to @peter279k)