python-jsonschema: Update to 4.16.0

 - Improve the base URI behavior when resolving a $ref to a resolution
 URI which is different from the resolved schema's declared $id.
 - Accessing jsonschema.draftN_format_checker is deprecated. Instead,
 if you want access to the format checker itself, it is exposed as
 jsonschema.validators.DraftNValidator.FORMAT_CHECKER on any
 jsonschema.protocols.Validator.

Signed-off-by: Javier Marcet <javier@marcet.info>