Update README.md

update dependency

Fix dockerfile, pinning node version

Merge branch 'oauth-instructions' of https://github.com/aaronraimist/mx-puppet-slack

update dependencies

fix emoji reactions

add support for ephemeral events

Document xoxs tokens

another word

word

Don't use code blocks because it resets the number

Add some more instructions on using OAuth

update dependency

update dependency

dependency update