Incorrect parameter type in generated fromValue method for enum of integer type: should be int, not String

Description

Incorrect paramater type for generated @JsonCreator function fromValue: should be int, not String.

Given the following enum definition:

"Purpose": {
    "type": "integer",
    "enum": [0, 1, 2, 3, 4]
}

... the following Java class is generated:

public enum Purpose {
  NUMBER_0(0),
  NUMBER_1(1),
  NUMBER_2(2),
  NUMBER_3(3),
  NUMBER_4(4);

  private Integer value;

  Purpose(Integer value) {
    this.value = value;
  }

  @JsonValue
  public Integer getValue() {
    return value;
  }

  @Override
  public String toString() {
    return String.valueOf(value);
  }

  @JsonCreator
  public static Purpose fromValue(String text) {
    for (Purpose b : Purpose.values()) {
      if (String.valueOf(b.value).equals(text)) {
        return b;
      }
    }
    return null;
  }
}

The relevant section is the @JsonCreator fromValue(String text) method. In earlier versions of io.swagger:swagger-codegen-cli:2.4.19 for instance, the generated parameter seems to be Integer, as expected.

The reason this is a major concern for us is that as of jackson-databind 2.11, the jackson object mapper correctly treats int values as ints, not strings.

Swagger-codegen version

3.0.25

Swagger declaration file content or url

"Purpose": {
    "type": "integer",
    "enum": [0, 1, 2, 3, 4]
}

Command line used for generation

Using swaggerCodegen 'io.swagger.codegen.v3:swagger-codegen-cli:3.0.25' with gradle plugin
'org.hidetake.swagger.generator' version '2.18.2'.

Steps to reproduce

Related issues/PRs

A related issue is filed in jackson-databind: https://github.com/FasterXML/jackson-databind/issues/2737

Suggest a fix/enhancement

Roll back implementation to what was used in version 2.4.19.

Start by comparing Java enum generation in swagger-codegen 3.0.25 with the earlier 2.4.19 behavior, focusing on the generated @JsonCreator fromValue method. Reproduce the Purpose integer enum from the issue and identify the generation template or entry point that selects its parameter type. Done means generated integer enums use an integer-compatible parameter and a regression case covers the output.