[REQ][Java][Spring] Add "@Deprecated" annotation to enum value in java code if enum value is deprecated in contract

Is your feature request related to a problem? Please describe.

I would like to propose an improvement for the generated java sources based on the API contract.

I think it would be very interesting to give the possibility to add the @Deprecated annotation to an enum value.

Describe the solution you'd like

For this, you could add a new extension, e.g. x-deprecated and add the value to deprecated.

    SaleBasePeriodType:
      type: string
      enum:
        - ACCUMULATED_CAMPAIGN
        - YESTERDAY
        - FISCAL_YEAR
        - LAST_FISCAL_YEAR
      x-deprecated: # new custom extension
        - ACCUMULATED_CAMPAIGN

Desired code:

public enum SaleBasePeriodTypeDTO {

  @Deprecated // <- annotation added
  ACCUMULATED_CAMPAIGN("ACCUMULATED_CAMPAIGN"),

  YESTERDAY("YESTERDAY"),

  FISCAL_YEAR("FISCAL_YEAR"),

  LAST_FISCAL_YEAR("LAST_FISCAL_YEAR");

  private String value;

  SaleBasePeriodTypeDTO(String value) {
    this.value = value;
  }

Start by locating the Java/Spring enum-generation entry point and how API contract extensions are read for enum values. Confirm the generated enum output for the proposed x-deprecated values, then identify or add the relevant generator tests; done means deprecated contract values receive @Deprecated while other values remain unchanged.