koenhoeymans

fix rdlowrey/auryn#129

1

This should fix #129 I've found this issue while looking for a solution to the same problem I had in my own DI library. It seems that PHP incorrectly states...

Yaml format requires non-dev symfony/yaml in composer.json

2

It seems that composer.json needs `symfony/yaml` as dependency for users who wish to use the yaml format, not just as a dev dependency (which are not installed by default anymore).