ci(node): build on latest node lts (v10) and stable (v11)

appveyor.yml

@@ -1,9 +1,9 @@
 environment:
   matrix:
-    - nodejs_version: 8
-    - nodejs_version: 9
+    - nodejs_version: '10'
+    - nodejs_version: '11'
 
-version: "{build}"
+version: '{build}'
 
 cache:
   - node_modules -> package.json
@@ -20,4 +20,4 @@ test_script:
   - npm run cov:check
 
 build: off
-deploy: off
+deploy: off