0.6.0

• Enhancement: Add packagist badge (#81), by @localheinz
• Update phpstan/phpstan from 0.12.2 to 0.12.3 (#82), by @violinist-bot
• Update phpspec/prophecy from 1.9.0 to 1.10.0 (#83), by @violinist-bot
• Update phpspec/prophecy from 1.10.0 to 1.10.1 (#85), by @violinist-bot
• Enhancement: Use ergebnis/composer-normalize instead of localheinz/composer-normalize (#86), by @localheinz
• Fix: Consistently quote strings in Yaml files (#87), by @localheinz
• Enhancement: Use ergebnis/php-cs-fixer-config (#88), by @localheinz
• Enhancement: Infer private property type from constructor (#89), by @localheinz
• Fix: Remove useless DocBlocks (#90), by @localheinz
• Fix: Namespace (#91), by @localheinz
• Enhancement: Add support for willImplement() (#92), by @localheinz
• Enhancement: Slightly clean up code (#93), by @localheinz
• Enhancement: Add support for willExtend() (#94), by @localheinz