Bump up nodejs to 10.15.3

gedorinku · gedorinku · commit 690ac78f5378 · 2019-05-15T19:38:27.000+09:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,6 +1,6 @@
 language: node_js
 node_js:
-  - '9.9'
+  - '10.15.3'
 
 script:
   - npm run build && npm run lint
