Log Message:
py-jsonschema: updated to 4.20.0

v4.20.0

* Properly consider items (and properties) to be evaluated by \ 
``unevaluatedItems`` (resp. ``unevaluatedProperties``) when behind a \ 
``$dynamicRef`` as specified by the 2020 and 2019 specifications.
* ``jsonschema.exceptions.ErrorTree.__setitem__`` is now deprecated.
  More broadly, in general users of ``jsonschema`` should never be mutating \ 
objects owned by the library.