build: Node.js@6.13

Author: dougwilson

.travis.yml

@@ -8,7 +8,7 @@ node_js:
   - "3.3"
   - "4.8"
   - "5.12"
-  - "6.12"
+  - "6.13"
   - "7.10"
   - "8.9"
   - "9.2"

appveyor.yml

@@ -8,7 +8,7 @@ environment:
     - nodejs_version: "3.3"
     - nodejs_version: "4.8"
     - nodejs_version: "5.12"
-    - nodejs_version: "6.12"
+    - nodejs_version: "6.13"
     - nodejs_version: "7.10"
     - nodejs_version: "8.9"
     - nodejs_version: "9.2"