Log Message:
py-zope.testing: updated to 4.9

4.9 (2021-01-08)
Make setupstack.txt test work again if the current directory is empty.

4.8 (2021-01-04)
Add support for Python 3.8 and 3.9.
Drop support for Python 3.3 and 3.4.
Extend IGNORE_EXCEPTION_MODULE_IN_PYTHON2 to cover also exceptions without \ 
arguments (thus without a colon on the last line of the traceback output).