[Java] Replace tab with 4-space for code indentation in Retrofit2

[wing328]

Description

Retrofit2 templates are using tab instead of 4-space for indentation

modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/api.mustache:  	"Content-Type:{{mediaType}}" 
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:        	baseUrl = baseUrl + "/";
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	  private final Gson gson;
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	  private final Type type;
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	  GsonResponseBodyConverterToString(Gson gson, Type type) {
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	    this.gson = gson;
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	    this.type = type;
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	  }
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	  @Override public T convert(ResponseBody value) throws IOException {
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	    String returned = value.string();
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	    try {
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	      return gson.fromJson(returned, type);
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	    }
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	    catch (JsonParseException e) {
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	 }
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	public static GsonCustomConverterFactory create(Gson gson) {
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	    return new GsonCustomConverterFactory(gson);
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	  }
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	  private final Gson gson;
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	  private final GsonConverterFactory gsonConverterFactory;
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	  private GsonCustomConverterFactory(Gson gson) {
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	    if (gson == null) throw new NullPointerException("gson == null");
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	    this.gson = gson;
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	    this.gsonConverterFactory = GsonConverterFactory.create(gson);
modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/ApiClient.mustache:	  }

We'll need to update these files to use 4-space for indentation and then review the code to make sure the code is aligned properly

Swagger-codegen version

Master

Suggest a Fix

If anyone has cycle to contribute the enhancement, please reply to let us know.

[ePaul]

Is this done with #5221, or is still a part open?

[wing328]

Closed via #5221