Used downgraded nodejs version for CI.

ciatph · ciatph · commit 38c8726d8b22 · 2019-11-13T17:33:20.000+08:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,6 +1,6 @@
 language: node_js
 node_js:
- - "node"
+ - "12.10"
 
 cache: npm
 
