http://raml.org/projects/projects lists https://github.com/spq-easy/raml under Perl. The YAML 1.2 spec states:

"The primary objective of this revision is to bring YAML into compliance with JSON as an official subset. YAML 1.2 is compatible with 1.1 for most practical applications."

You'd have to check the fine points of the documentation to find out if the differences have a substantial impact.