YAML merge keys `<<: ` not supported

[ioggstream]

YAML merge keys <<: not supported

Context

It seems that yaml merge keys are not supported in openapi spec.

Current Behavior

Merge keys are not expanded

Expected Behavior

Correct rendering

Possible Workaround/Solution

Integrate merge keys

Steps to Reproduce

1. See https://elements-demo.stoplight.io/?spec=https://raw.githubusercontent.com/teamdigitale/api-openapi-samples/master/openapi-v3/defibrillatori-example.yaml#/schemas/DefibrillatoriGeo