[BUG] packageName ignored by maven plugin

Created by: Zomzog

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• What's the version of OpenAPI Generator used?
• Have you search for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Bounty to sponsor the fix (example)

Description

packageName not used by maven plugin, infrastructure is genereted in default package.

openapi-generator version

3.2.2 and 4.0.0-SNAPSHOT

OpenAPI declaration file content or url

Maven config

<groupId>org.openapitools</groupId>
<artifactId>openapi-generator-maven-plugin</artifactId>
<executions>
    <execution>
        <goals>
            <goal>generate</goal>
        </goals>
        <configuration>
            <inputSpec>${project.basedir}/src/main/resources/swagger.json</inputSpec>
            <generatorName>kotlin</generatorName>
            <configOptions>
                <sourceFolder>src/gen/kotlin/main</sourceFolder>
            </configOptions>
            <packageName>bzh.zomzog.utils</packageName>
            <generateSupportingFiles>true</generateSupportingFiles>
        </configuration>
    </execution>
</executions>

Command line used for generation

mvn clean install

Steps to reproduce

Generate a kotlin client with custom packageName

Related issues/PRs

Suggest a fix

Add support of packageName to maven plugin