chore: drop node 6 (#78)

Author: curbengh

.travis.yml

@@ -8,8 +8,8 @@ cache:
     - node_modules
 
 node_js:
-  - "6"
   - "8"
+  - "10"
   - "node"
 
 script:

appveyor.yml

@@ -5,8 +5,9 @@ init:
 # Test against these versions of Node.js.
 environment:
   matrix:
-    - nodejs_version: "LTS"
-    - nodejs_version: "Stable"
+    - nodejs_version: "8"
+    - nodejs_version: "10"
+    - nodejs_version: "12"
 
 matrix:
   fast_finish: true

package.json

@@ -61,6 +61,6 @@
     "sinon": "^7.3.2"
   },
   "engines": {
-    "node": ">=6.9.0"
+    "node": ">=8.6.0"
   }
 }