Update how webhooks are sent

Fixes #6 (closed)

.gitlab-ci.yml

@@ -22,8 +22,8 @@ format:
         # Add here all the dependencies, or use glide/govendor to get
         # them automatically.
         # - curl https://glide.sh/get | sh
-        - go get github.com/42wim/matterbridge/matterhook
         - go get github.com/asaskevich/govalidator
+        - go get github.com/ashwanthkumar/slack-go-webhook
         - go get github.com/hpcloud/tail
         - go get github.com/alecthomas/kingpin
         - go tool vet -composites=false -shadow=true *.go