[BUG] [JAVA] Enum path parameter generated as string

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?

Description

When using an enum as a path parameter, the generated client uses a String as argument

openapi-generator version

6.0.1, but also reproduced in latest master (6.1.1)

OpenAPI declaration file content or url

https://gist.github.com/RInverid/5f4f2c0bf905e9007880671d6b10460d

Generation Details

using the java language, I tried the default & native library configuration, issue still persists

Suggest a fix

I would like the enum classes to be generated (perhaps an inner class of the generated Api class) to be used as arguments.
Or at minimum use the defined enum values as validation for the string input

Start with the OpenAPI declaration in the linked gist and generate the Java client using the default and native library configurations. Compare the path parameter type with the declared enum; done means the generated client represents the enum appropriately or validates the defined enum values instead of accepting an unrestricted String.