Log Message:
py-sphinx: updated to 2.4.2

Release 2.4.2:

Bugs fixed
* autodoc: ``autodoc.typehints`` crashed when variable has unbound object
  as a value
* autodoc: separator for keyword only arguments is not shown
* autodoc: IndexError is raised on suppressed type_comment found
* autodoc: typehints extension does not support parallel build
* autodoc: TypeError is raised on fetching type annotations
* crashed when extension assigns a value to ``env.indexentries``
* text: Remove debug print
* viewcode: Avoid to crash when non-python code given