[FEATURE] Support for AsyncAPI 3.*.

[hartmanjan1970]

Why do we need this improvement?

The AsyncAPI 3.0.0 is available for a while now, so should this template supportt this new version of AsyncAPI or not?

How will this change help?

To keep the template in sync with the current available specification versions.

Screenshots

No response

How could it be implemented/designed?

Be able to generate code from AsyncAPI contracts made with asyncapi specification version 3.0.0

🚧 Breaking changes

Yes

👀 Have you checked for similar open issues?

• I checked and didn't find a similar issue

🏢 Have you read the Contributing Guidelines?

• I have read the Contributing Guidelines

Are you willing to work on this issue?

None

[github-actions]

Welcome to AsyncAPI. Thanks a lot for reporting your first issue. Please check out our contributors guide and the instructions about a basic recommended setup useful for opening a pull request.
Keep in mind there are also other channels you can use to interact with AsyncAPI community. For more details check out this issue.

[paderick]

Any updates here?