Release 2.0.0 - First test release

This is version 2.+ of the Slack 2 plugin, which uses the current slack_sdk package instead of the older slackclient package. The SDK requires Python 3, which this plugin supports by running the Python3 code in a separate process which communicates with the Python2 plugin.

See the readme file for requirements, and the Wiki to configuration instructions (link in ReadMe).