Update python-nwdiag to version 3.0.0 / rev 6 via SR 990240
https://build.opensuse.org/request/show/990240
by user dirkmueller + RBrownFactory
- update to 3.0.0:
* Drop python3.6 support
* Use funcparserlib-1.0.0a0 or newer to support new python versions
* Allow to write multiline string via triple quotes (""" ... """)