chore(travis): add Node.js 10 (#425)

Author: DanielRuf

.travis.yml

@@ -17,6 +17,9 @@ matrix:
     - os: linux
       node_js: "stable"
       env: JOB_PART=integration
+    - os: linux
+      node_js: "10"
+      env: JOB_PART=integration
     - os: linux
       node_js: "8"
       env: JOB_PART=integration
@@ -55,4 +58,4 @@ jobs:
     - stage: NPM release
       if: branch = master
       node_js: "lts/*"
-      script: npm run travis-deploy-once "npm run semantic-release"
+      script: npm run travis-deploy-once "npm run semantic-release"