Fix parse exceptions: "Numeric keys are not supported"
Fix parse exceptions: "Numeric keys are not supported"

due to deprecation in Symfony's Yaml component v4

janvernieuwe/grumphp,aderuwe/grumphp,janvernieuwe/grumphp,tombevers/grumphp,jyggen/grumphp,phpro/grumphp,aderuwe/grumphp,jyggen/grumphp,veewee/grumphp,Big-Shark/grumphp,tombevers/grumphp,phpro/grumphp,Big-Shark/grumphp,veewee/grumphp