[Kotlin] Jackson is outdated

Created by: zapodot

Description

The project is generated with an outdated version of Jackson when language is "kotlin" and serializationLibrary is "jackson". It also references the obsolete JDK8 module for Jackson which is no longer needed

openapi-generator version

5.1.0-SNAPSHOT

Command line used for generation

maven plugin configuration:

<configuration>
    <inputSpec>${project.build.directory}/openapi.json</inputSpec>
    <generatorName>kotlin</generatorName>
    <configOptions>
        <dateLibrary>java8</dateLibrary>
        <java11>true</java11>
        <useCoroutines>true</useCoroutines>
        <collectionType>list</collectionType>
        <enumPropertyNaming>UPPERCASE</enumPropertyNaming>
        <serializationLibrary>jackson</serializationLibrary>
    </configOptions>
    <packageName>org.example</packageName>
    <library>jvm-okhttp4</library>
    <generateApiTests>false</generateApiTests>
    <generateModelTests>false</generateModelTests>
    <generateSupportingFiles>true</generateSupportingFiles>
    <addCompileSourceRoot>true</addCompileSourceRoot>
</configuration>

Steps to reproduce

Related issues/PRs

#8689

Suggest a fix/enhancement

Adjust mustache templates to use an updated version of Jackson and remove all references to the JDK8 module as all functionality has been merged into jackson-core in the latest versions I will provide a PR that will solve this issue