Use NodeJS 8.9.3 to match the VSCode version

.travis.yml

@@ -20,6 +20,7 @@ addons:
 
 before_install:
   - |
+    nvm install 8.9.3 || exit 2
     if [ $TRAVIS_OS_NAME == "linux" ]; then
       export DISPLAY=:99.0
       sh -e /etc/init.d/xvfb start

package.json

@@ -988,7 +988,7 @@
     "@types/js-yaml": "^3.5.28",
     "@types/json5": "~0.0.29",
     "@types/mocha": "~2.2.41",
-    "@types/node": "~8.0.0",
+    "@types/node": "~8.9.3",
     "@types/rimraf": "^0.0.28",
     "@types/sinon": "~4.3.3",
     "@types/tmp": "^0.0.33",

yarn.lock

@@ -80,9 +80,10 @@
   version "10.0.8"
   resolved "https://registry.yarnpkg.com/@types/node/-/node-10.0.8.tgz#37b4d91d4e958e4c2ba0be2b86e7ed4ff19b0858"
 
-"@types/node@~8.0.0":
+"@types/node@~8.9.3":
-  version "8.0.58"
+  version "8.9.5"
-  resolved "https://registry.yarnpkg.com/@types/node/-/node-8.0.58.tgz#5b3881c0be3a646874803fee3197ea7f1ed6df90"
+  resolved "https://registry.yarnpkg.com/@types/node/-/node-8.9.5.tgz#162b864bc70be077e6db212b322754917929e976"
+  integrity sha512-jRHfWsvyMtXdbhnz5CVHxaBgnV6duZnPlQuRSo/dm/GnmikNcmZhxIES4E9OZjUmQ8C+HCl4KJux+cXN/ErGDQ==
 
 "@types/rimraf@^0.0.28":
   version "0.0.28"