net-mgmt/py-napalm-logs: Update to 0.9

• Switch to GitHub for a while to make use of the test suite.

• Add a "do-test" target to make future QA easier.

Changelog since 0.7:

https://napalm-logs.com/en/latest/releases/0.9.0.html
https://napalm-logs.com/en/latest/releases/0.8.0.html

MFH: 2020Q2 (blanket: Fix runtime issues with Python 3.7)