Drop Node.js 6 from .travis.yml

Node.js 6 is EOL. I get the following error in a library that does not support Node.js 6. ``` node_modules/eslint/lib/cli-engine/cli-engine.js:257 ...calculateStatsPerFile(messages) ^^^ ```
zeke · Jul 11, 2019 · 6b72431 · 6b72431
1 parent 7579a91
commit 6b72431
Showing 1 changed file with 0 additions and 1 deletion.
diff --git a/.travis.yml b/.travis.yml
@@ -1,6 +1,5 @@
 language: node_js
 node_js:
-  - "6"
   - "8"
   - "10"
   - "12"