OAS2->3 converter doesn't update $refs inside allOf

[hkosova]

https://converter.swagger.io converts this OAS2 definition:

swagger: '2.0'
info:
  title: Conversion test
  version: '1.0.0'
paths: {}

definitions:
  Foo:
    type: object
    properties:
      foo:
        type: string
  Bar:
    type: object
    properties:
      bar1:
        $ref: '#/definitions/Foo'     # This $ref is converted properly to `#/components/schemas`
      bar2:
        allOf:
          - $ref: '#/definitions/Foo' # This $ref remains as `#/definitions`

to this OAS3 definition:

...
components:
  schemas:
    Foo:
      type: object
      properties:
        foo:
          type: string
    Bar:
      type: object
      properties:
        bar1:
          $ref: '#/components/schemas/Foo'
        bar2:
          type: object
          allOf:
          - $ref: '#/definitions/Foo'   # should be '#/components/schemas/Foo'

Note that the $ref inside allOf is not updated.

[gracekarina]

thanks @hkosova @r-sreesaran
closed by #1302