Generate Valid OpenAPI When JWTSecurity is Used

[EtienneDufresne]

Adding the "In" and "Name" field to the JWTSecurity scheme expression so it generates a valid OpenAPI securityDefinitions section.

Before this change, a design with the following security scheme would generate an invalid OpenAPI securityDefinitions section.

Design:

var jwtSecurity = dsl.JWTSecurity("jwt", func() {
	dsl.Description(`Secures endpoint by requiring a valid JWT token.`)
})

Output OpenAPI without these changes:

securityDefinitions:
  jwt:
    type: apiKey
    description: |
      Secures endpoint by requiring a valid JWT token.
      **Security Scopes**:

When copy pasted to https://editor.swagger.io/, the OpenAPI causes:

Schema error at securityDefinitions['jwt']
should have required property 'flow'
missingProperty: flow

Schema error at securityDefinitions['jwt'].type
should be equal to one of the allowed values
allowedValues: basic, oauth2

This change populates the required in and name fields when specifying an apiKey securityDefinitions and gets rid of the https://editor.swagger.io/ errors.

Output OpenAPI with these changes:

securityDefinitions:
  jwt:
    type: apiKey
    description: |
      Secures endpoint by requiring a valid JWT token.
      **Security Scopes**:
    name: Authorization
    in: header

For more information please see:

• https://github.com/OAI/OpenAPI-Specification/blob/master/versions/2.0.md#securityDefinitionsObject
• security: add support for Authorization header with Bearer authentication scheme OAI/OpenAPI-Specification#583

[raphael]

Thank you for the PR and the the details!