[cmaster-next] Slack - upgrade to standard edition?

[Martin Winter]

Donald,
(and everyone else working on it)

Thanks for setting up Slack. We (NetDEF) can get a free upgrade to the 
standard edition
as part of bing a 501c3 non-profit.

See https://freerangerouting.slack.com/pricing for difference between 
Free and Standard
model.

Happy to do this if this community thinks Slack is useful. Please be 
aware that it’s
free “only” up to 250 users - and 85% discount above it.

We can only do this for one Slack - so we may want to wait until 
everyone confirms
the new selected name (i.e. no legal issues)

- Martin