Update spec to OpenAPI 3.0.1
Update spec to OpenAPI 3.0.1

Convert to using an OpenAPI 3.0.1 swagger spec

Bug: T218218
Change-Id: Id07aa0efe50b825b982f64ca2b42570ece8fce9e

wikimedia/mathoid,wikimedia/mathoid,wikimedia/mathoid,wikimedia/mathoid