[json] JSONSchema draft 2019-09 support

[srounce]

JSONSchema draft-07 is currently supported but http://json-schema.org/draft/2019-09/schema# does not currently load, or at least no completion or validation functionality is able to be provided from it.

[vscodebot]

(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:

• [json] Override/disable json-schema for package.json (#74943)

[aeschli]

The implementation will be in https://github.com/microsoft/vscode-json-languageservice

[Relequestual]

As an FYI, OpenAPI Specification 3.1 defines using JSON Schema 2020-12.
We're working on the test suite.
There are a few implementations of 2020-12 already should anyone wish to try it.