Use matterbridge vendored slack

vendor/github.com/nlopes/slack/websocket_reactions.go

@@ -1,25 +0,0 @@
-package slack
-
-// reactionItem is a lighter-weight item than is returned by the reactions list.
-type reactionItem struct {
-	Type        string `json:"type"`
-	Channel     string `json:"channel,omitempty"`
-	File        string `json:"file,omitempty"`
-	FileComment string `json:"file_comment,omitempty"`
-	Timestamp   string `json:"ts,omitempty"`
-}
-
-type reactionEvent struct {
-	Type           string       `json:"type"`
-	User           string       `json:"user"`
-	ItemUser       string       `json:"item_user"`
-	Item           reactionItem `json:"item"`
-	Reaction       string       `json:"reaction"`
-	EventTimestamp string       `json:"event_ts"`
-}
-
-// ReactionAddedEvent represents the Reaction added event
-type ReactionAddedEvent reactionEvent
-
-// ReactionRemovedEvent represents the Reaction removed event
-type ReactionRemovedEvent reactionEvent