[bisq-network/bisq-docs] Update discussion infrastructure (#200)

[Alfavio]

The Bisq no longer uses the Slack as a discussion infrastructure. In docs is mentioned old information about discussion infrastructure _(eg. [proposals](https://docs.bisq.network/proposals.html#slack))_. It needs to be corrected to not confuse new contributors.

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/bisq-network/bisq-docs/issues/200
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bisq.network/pipermail/bisq-github/attachments/20200520/b67ab5f1/attachment-0001.html>