feat: drop support for node 6

BREAKING:  Dropped support for node 6. Use at least node 8 (included in Meteor 1.6 and up, see https://blog.meteor.com/announcing-meteor-1-6-abf30f29e2c6)

Author: dferber90

.travis.yml

@@ -8,9 +8,9 @@ notifications:
   email: false
 
 node_js:
-  - 6
   - 8
   - 10
+  - 12
 
 script:
   - npm run test || travis_terminate 1
@@ -20,7 +20,7 @@ jobs:
   include:
     # Define the release stage that runs semantic-release
     - stage: release
-      node_js: 8
+      node_js: 12
       env: NODE_ENV=production
       before_install: skip
       script: skip

package.json

@@ -56,7 +56,7 @@
     "eslint": ">= 3.7.0 < 7"
   },
   "engines": {
-    "node": ">=6"
+    "node": ">=8"
   },
   "keywords": [
     "eslint",