Bridge widgets as pinned messages #468
Description
Widgets in matrix are embedded web pages which some clients can display. To bridge them to slack we should send a normal message with the URL and then pin that message so it's easy to find for people on slack.
Matrix widgets are in the process of being add to the specification here: matrix-org/matrix-spec-proposals#2764 the relevant documentation of the state event can at the time of writing be seen in this preview when one of these is added or removed (content is blank) a slack pinned message would need to be added (https://api.slack.com/events/pin_added) or remove (https://api.slack.com/events/pin_removed).