build: Node.js@10.15

zbjornson · zbjornson · commit ef644c25bf47 · 2019-03-08T12:51:51.000-08:00
v10 has emitter.off(), which is used in the next commit
diff --git a/.travis.yml b/.travis.yml
@@ -12,6 +12,7 @@ node_js:
   - "7.10"
   - "8.11"
   - "9.11"
+  - "10.15"
 sudo: false
 cache:
   directories:
