Add tests for Node.js 13 (#381)

ehmicky · sindresorhus · commit 4f49253de695 · 2019-10-24T10:49:44.000+07:00
diff --git a/.travis.yml b/.travis.yml
@@ -4,6 +4,7 @@ os:
   - windows
 language: node_js
 node_js:
+  - '13'
   - '12'
   - '10'
   - '8'
