Empty SecurityRequirement in YAML file

[NukeBoy]

When trying to write a Security Requirement object to a YAML file:
$openapi->security = [new SecurityRequirement(['Bearer' => []])];
The result is:

security:
        -
          Bearer: {  }

When expected:

security:
        -
          Bearer: []

When writing to a JSON file, everything is fine:

"security": [
    {
         "Bearer": []
    }
]

[cebe]

seems symfony/yaml is interpreting this wrong... not sure how to solve it, if it would print an array intead of object we could just pass a stdClass object, but I don't know a way to force the type the other way round...

[coatesap]

Potential fix for this suggested in #52