Add defusedxml into extras_require (!351) · Merge requests · openpyxl / openpyxl

Created originally on Bitbucket by jiajunsu

Changesets for this Pull Request have not been imported, because it had been already declined on Bitbucket. Marked as closed by the import user.

The dependency of defusedxml has been imported since[0],
but we did not declare it in setup.py. Users may not
know what version we support[1].

Now add the dependency in extras_require to make requirements
more clear.

Add defusedxml into extras_require