Petstore 2.0 is outdated, let’s use Petstore 3.1

[hanspagel]

Describe the feature

The README is promoting the super outdated Petstore 2.0 version (using the not-open Swagger 2.0 specification), but the community mostly moved forward to OpenAPI 3.1 (3.2 is around the corner already).

I tried replacing the URL with https://petstore31.swagger.io/api/v31/openapi.json

Unfortunately, Swagger seems to block requests (or not add CORS headers).

I think we’ll set up a mirror, so we can use it freely.

Additional information

• Would you be willing to help implement this feature?