travis: only deploy with one ruby version

Tero Marttila · Tero Marttila · commit 419a589a1af2 · 2017-07-21T20:29:21.000+03:00
diff --git a/.travis.yml b/.travis.yml
@@ -19,3 +19,4 @@ deploy:
   on:
     tags: true
     repo: kontena/kontena-websocket-client
+    rvm: 2.3.3
