Upgraded slack-ruby-client.

Author: dblock

Gemfile.lock

@@ -14,7 +14,7 @@ GEM
     async (1.10.3)
       nio4r (~> 2.3)
       timers (~> 4.1)
-    async-io (1.15.5)
+    async-io (1.16.0)
       async (~> 1.3)
     async-websocket (0.6.1)
       async-io
@@ -205,7 +205,7 @@ GEM
       rack-server-pages
       slack-ruby-bot
       unicorn
-    slack-ruby-client (0.13.0)
+    slack-ruby-client (0.13.1)
       activesupport
       faraday (>= 0.9)
       faraday_middleware