Updated the Slack invitation link in the README (#2128)
Updated the Slack invitation link in the README (#2128)

When visiting the current Slack invitation link you reach a page that displays the message
"This link is no longer active"

This commit updates the Slack invitation link in the README Questions/Discussion section.

https://join.slack.com/t/pynet/shared_invite/zt-km2k3upf-AkWHY4YEx3sI1R5irMmc7Q

Fixes #2122

	modified:   README.md
ktbyers/netmiko,ktbyers/netmiko