Allow truffleruby to fail.

ioquatix · ioquatix · commit 10292baa85bb · 2020-03-31T00:34:01.000+13:00
diff --git a/.travis.yml b/.travis.yml
@@ -15,4 +15,5 @@ matrix:
     - rvm: ruby-head
   allow_failures:
     - rvm: ruby-head
+    - rvm: truffleruby
     - rvm: jruby-head
