Default specification for OpenAPI3 not available

[Arvoreen75]

Hello,

default specifications are not available, could you change the default to
https://spec.openapis.org/oas/3.0/schema/2021-09-28
which seems to be the latest 3.0 specifications and are available

Sincerely
Pol Bettinger

[jhthorsen]

Please open a pull request with the new specification.