[Go] [Java] [Client] Adding required to fields

Description

Swagger-codegen both for go and java can't add required to fields when reusing object.
related to #722

Swagger-codegen version

2.3.1
3.0.4

openapi 2/3

Swagger declaration file content or url

swagger: '2.0'
info:
  description: Example
  title: Example
  version: '1.0.0'
consumes:
  - application/json
produces:
  - application/json
paths: {}
definitions:
  InputWithRequired:
    required:
      - id
      - number
    allOf:
      - $ref: '#/definitions/Input'
  Input:
    type: object
    properties:
      id:
        type: number
        example: 53
      number:
        type: string
        example: "0000000024"

openapi: 3.0.0
info:
  description: Example
  title: Example
  version: '1.0.0'
paths: {}
components:
  schemas:
    InputWithRequired:
      required:
        - id
        - number
      allOf:
        - $ref: '#/components/schemas/Input'
    Input:
      type: object
      properties:
        id:
          type: number
          example: 53
        number:
          type: string
          example: "0000000024"

Documentaion generated with these specs is correct, it specifies that for InputWithRequired id and number fields are required, but for Input they are optional. However generated models both set fields as optional.

Start by reproducing the issue with the provided Swagger 2.0 and OpenAPI 3.0 declarations using the Go and Java generators. Compare the generated models for InputWithRequired and Input; done means id and number are required only in InputWithRequired, while remaining optional in Input.