[BUG] kotlin-spring, spring-boot code generator creates invalid enums

Description

Generated enum case is unusable:

    enum class RequiredActions(val value: kotlin.String) {

        @JsonProperty("update_user_locale") updateUserLocale("update_user_locale"),
        @JsonProperty("CONFIGURE_TOTP") cONFIGURETOTP("CONFIGURE_TOTP"),
        @JsonProperty("VERIFY_EMAIL") vERIFYEMAIL("VERIFY_EMAIL"),
        @JsonProperty("UPDATE_PASSWORD") uPDATEPASSWORD("UPDATE_PASSWORD"),
        @JsonProperty("UPDATE_PROFILE") uPDATEPROFILE("UPDATE_PROFILE")
    }

Using RequiredActions.valueOf will of course fail when trying to translate something like CONFIGURE_TOTP to cONFIGURETOTP.

openapi-generator version

6.0.0

OpenAPI declaration file content or url

in an object as property:

        requiredActions:
          type: array
          items:
            type: string
            enum:
              - update_user_locale
              - CONFIGURE_TOTP
              - VERIFY_EMAIL
              - UPDATE_PASSWORD
              - UPDATE_PROFILE

Generation Details

openApiGenerate {
    // https://openapi-generator.tech/docs/generators/kotlin-spring
    generatorName.set("kotlin-spring")
    library.set("spring-boot")

    inputSpec.set(openAPISpecFile)
    outputDir.set("$buildDir/$openAPIGenOutBase")

    packageName.set(openAPIBasePackage)
    apiPackage.set("$openAPIBasePackage.api")
    invokerPackage.set("$openAPIBasePackage.client")
    modelPackage.set("$openAPIBasePackage.model")

    modelNameSuffix.set("Dto")
    typeMappings.set(
        mapOf(
            "DateTime" to "Instant"
        )
    )
    importMappings.set(
        mapOf(
            "Instant" to "java.time.Instant"
        )
    )
    configOptions.set(
        mapOf(
            "useBeanValidation" to "true",
            "delegatePattern" to "true",
            "useTags" to "true",
            "exceptionHandler" to "false",
            "gradleBuildFile" to "false",
            "reactive" to "false",
            "serviceInterface" to "false",
            "sortModelPropertiesByRequiredFlag" to "true",
            "sortParamsByRequiredFlag" to "true",
            "swaggerAnnotations" to "true",
        )
    )
}

Steps to reproduce

• create simple object containing the property above.
• use kotlin-spring, spring-boot generator to create kotlin code

Suggest a fix

Keep upper/lower case as it is.

Start by running the supplied OpenAPI enum and kotlin-spring/spring-boot generation configuration against version 6.0.0. Trace the generator's enum-name handling and verify that generated constants preserve the declared casing, so values such as CONFIGURE_TOTP can be resolved with valueOf.