[BUG] [java] [resttemplate] Generated alias models missing JsonTypeName import

Created by: mikesaurus

Description

When generating client code with openapi-generator and the generateAliasAsModel option set to true, model classes generated from aliases are missing an import statement for the JsonTypeName annotation and fail to compile.

openapi-generator version

5.0.0-x

OpenAPI declaration file content or url

Example swagger contract.

Generation Details

The code is being generated using the Maven plugin. See example project.

Steps to reproduce

1. See example project README.
2. Change the openapi-generator-maven-plugin.version in the POM file to any 5.0.0-x version and build.

Related issues/PRs

None.

Suggest a fix

Include the JsonTypeName import for both standard and alias model classes.