0.5.0

• Update phpunit/phpunit from 7.2.6 to 7.5.14 (#55), by @violinist-bot
• Enhancement: Allow installation with phpstan/phpstan:~0.12.2 (#67), by @localheinz
• Enhancement: Switch to using GitHub actions (#68), by @localheinz
• Fix: Reference (#70), by @localheinz
• Update phpunit/phpunit from 7.5.16 to 7.5.18 (#65), by @violinist-bot
• Update phpspec/prophecy from 1.8.1 to 1.9.0 (#63), by @violinist-bot
• Enhancement: Run builds on PHP 7.4 (#71), by @localheinz
• Enhancement: Add changelog (#72), by @localheinz