Add warnings on json schema deprecated fields

[adodon2go]

In many schemas, you may want to deprecate fields and log warnings when these fields are used without causing a validation to fail entirely.
For draft 2019-09 JSON Schema, the deprecated annotation keyword was added.
As an enhancement, it would be great if those deprecated fields will be highlighted to the end user in the form of warnings. In this way they can be notified that support for those will be dropped soon and they need to adapt accordingly.

[santhosh-tekuri]

linting is no in scope of this project.