[BUG][ALL] HTTP Auth scheme names are (incorrectly) case-sensitive

Description

The API generator does not generate authorization/authentication code when the user inserts a security scheme like so:

components:
  securitySchemes:
    bearerToken:
      type: http
      scheme: Bearer

Note that "Bearer" is title-cased. It works if the scheme is instead lowercase "bearer".

Even though the spec is not clear on the subject, according to the spec author HTTP auth schemes should be case-insensitive. Even if the schemes were case-sensitive, the IANA registry's canonical cases for the two most common schemes are "Bearer" and "Basic".

openapi-generator version

4.3.0

OpenAPI declaration file content or url

See yaml snippet in description above

Command line used for generation

openapi-generator generate -i $OAS3_YAML_FILE -g scala-akka -o /tmp/apiclient-test

I have also tested this with ruby and bash generators

Suggest a fix

I've opened a PR in swagger-api/swagger-js#1531; I don't know where the relevant code is in this project, though.

Start with the YAML securitySchemes snippet and run the documented openapi-generator command for the scala-akka generator. Reproduce the difference between title-cased and lowercase Bearer values, then check the ruby and bash generators mentioned in the report; done means HTTP auth code is generated consistently for case-insensitive scheme names.