Fully support OAS 3.1

[nfroidure]

OAS 3.1 brings support for a lot a new features, especially JSON Schema full support (patternProperties 🙏). https://www.openapis.org/blog/2020/06/18/openapi-3-1-0-rc0-its-here

Here is a todo list to complete in order to ship OAS 3.1 support:

• Update the OpenAPI type generator to support patternProperties Support patternProperties horiuchi/dtsgenerator#435
• support webhooks #187
• support callbacks #188
• runtime expressions : https://spec.openapis.org/oas/v3.1.0#runtime-expressions
• reusable examples
• upgrade or substitute @apidevtools/swagger-parser (see Add support to openAPI 3.1.* APIDevTools/swagger-parser#169 )
• upgrade swagger-ui ( see OpenAPI 3.1 swagger-api/swagger-ui#5891 )
• use OAS3.1 types (import OpenAPIV3_1 instead of OpenAPIV3 from https://github.com/kogosoftwarellc/open-api/tree/master/packages/openapi-types )
• update schema validator ( [openapi-schema-validator] Add support for OAS v3.1.0 schema kogosoftwarellc/open-api#837 )

[nfroidure]

Finally created https://github.com/nfroidure/schema2dts. Till have to check 3.1 features and implement it.

[nfroidure]

The schema validator may be changed for IBM/openapi-validator#545 to move forward on this long running issue.