Alternative for openapi-core

[kigawas]

Just spent some time playing with pyotr, I found that its dependency openapi-core is rather primitive and it lacks lots of features.

It has too many restrictions on security scheme:

1. you can only define API_KEY and HTTP provider
2. if you define more than one schemes like below, you can only use the first one (probably a bug in RequestValidator._get_security, it alway returns the first scheme)

      security:
        - petstore_auth:
            - 'write:pets'
            - 'read:pets'
        - api_key: []

[berislavlopac]

I'm definitely open to improvements in this area, but I am not aware of a better alternative to openapi-core. Suggestions welcome!

[kigawas]

In effect I found this connexion's sanic PR pretty useful, though connexion is not actively maintained 😄

https://github.com/zalando/connexion/pull/1250