temporarily disable node@15 in travis because of npm@7 bug

zloirock · zloirock · commit 42e22ad0d245 · 2020-10-26T13:51:04.000+07:00
npm/cli#1865
diff --git a/.travis.yml b/.travis.yml
@@ -1,6 +1,6 @@
 language: node_js
 node_js:
-  - '15'
+# - '15'
   - '14.14'
   - '12.13'
   - '10.13'
