[JAVA][Retrofit2][swagger-codegen-cli-3.0.4] Version 3.0.4 don't have the template fixes from swagger code gen 2.x

Description

When using swagger-codegen-cli-3.0.4 and add for configuration that we want to use Retrofit2 as library and with the use of RxJava2 ('useRxJava2' at true).

We have an issue with the generation where a wrong annotation is used (retrofit2.http.Path instead of retrofit2.http.Query) This issue is already fixed since a very long time in the version 2. But it still present in the version 3.0.4.

I tried to fork the project to mirror the fix and make a merge-request for the v3 but the template files are not present anymore. In the source file for the v3.

I dezip the jar, in the file handlebars\Java\libraries\retrofit2\queryParams.mustache we should have
{{#is this 'query-param'}}@retrofit2.http.Query("{{baseName}}") {{{dataType}}} {{paramName}}{{/is}}
instead of
{{#is this 'query-param'}}@retrofit2.http.Path("{{baseName}}") {{{dataType}}} {{paramName}}{{/is}}

A funny thing is that the files from the v2 are also present in the same jar and HAVE the related fixes.

Also there is a invalid character in /handlebars/Java/libraries/retrofit2/api_test.mustache . A letter f is not an ascii char but a really funny char who appeared like a wild pokemon.

Swagger-codegen version

swagger-codegen-cli-3.0.4-SNAPSHOT

Swagger declaration file content or url

openapi: "3.0.0"
info:
  version: 1.0.0
  title: Swagger Petstore
  license:
    name: MIT
servers:
  - url: http://petstore.swagger.io/v1
paths:
  /pets:
    get:
      summary: List all pets
      operationId: listPets
      tags:
        - pets
      parameters:
        - name: limit
          in: query
          description: How many items to return at one time (max 100)
          required: false
          schema:
            type: integer
            format: int32
      responses:
        '200':
          description: A paged array of pets
          headers:
            x-next:
              description: A link to the next page of responses
              schema:
                type: string
          content:
            application/json:    
              schema:
                $ref: "#/components/schemas/Pets"
        default:
          description: unexpected error
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Error"
    post:
      summary: Create a pet
      operationId: createPets
      tags:
        - pets
      responses:
        '201':
          description: Null response
        default:
          description: unexpected error
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Error"
  /pets/{petId}:
    get:
      summary: Info for a specific pet
      operationId: showPetById
      tags:
        - pets
      parameters:
        - name: petId
          in: path
          required: true
          description: The id of the pet to retrieve
          schema:
            type: string
      responses:
        '200':
          description: Expected response to a valid request
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Pets"
        default:
          description: unexpected error
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Error"
components:
  schemas:
    Pet:
      required:
        - id
        - name
      properties:
        id:
          type: integer
          format: int64
        name:
          type: string
        tag:
          type: string
    Pets:
      type: array
      items:
        $ref: "#/components/schemas/Pet"
    Error:
      required:
        - code
        - message
      properties:
        code:
          type: integer
          format: int32
        message:
          type: string

Command line used for generation

java -jar swagger-codegen-cli-3.0.4-20181205.061456-5.jar generate -i petstore.yaml -l java --library retrofit2 --api-package io.petstore.api --model-package io.petstore.model -o api/petstore -Dapis,models --additional-properties java8=true,dateLibrary=java8,useRxJava2=true

Steps to reproduce

Use the command and see.

Related issues/PRs

Suggest a fix/enhancement

For handlebars\Java\libraries\retrofit2\queryParams.mustache copy the content from Java\libraries\retrofit2\queryParams.mustache

Fix the wrong and funny character in _handlebars\Java\libraries\retrofit2\api_test.mustache by using the file from Java\libraries\retrofit2\api_test.mustache.

Start with handlebars/Java/libraries/retrofit2/queryParams.mustache and handlebars/Java/libraries/retrofit2/api_test.mustache, comparing them with the corresponding Java/libraries/retrofit2 files mentioned in the issue. Run the provided Java generation command with Retrofit2 and useRxJava2 enabled; done means query parameters use the Query annotation and the invalid character is removed from the generated test template.