Improve CI

- Add npm auto-release
- Remove Nodejs v8 support
- Add Nodejs 13 support
- Add lint
- Close #30

.travis.yml

@@ -1,9 +1,22 @@
 language: node_js
 node_js:
-  - v12
   - v10
-  - v8
+  - v12
+  - v13
 install:
   - npm install
 test:
+  - npm run lint
   - npm run test
+
+jobs:
+  include:
+  - stage: npm Deployment
+    deploy:
+      edge: true
+      provider: npm
+      skip_cleanup: true
+      email: "$NPM_EMAIL"
+      api_key: "$NPM_TOKEN"
+      on:
+        tags: true