chore: travis updated configs and testing platforms

.travis.yml

@@ -1,7 +1,27 @@
+sudo: false
+
 language: node_js
+
+addons:
+  sauce_connect: true
+
+cache:
+  directories:
+    - node_modules
+
 node_js:
-  - 0.8
-  - 0.10
-  - 0.11
+   - 0.10 # to be removed 2016-10-01
+   - 0.12 # to be removed 2016-12-31
+   - 4 # to be removed 2018-04-01
+   - 6 # to be removed 2019-04-01
+   - lts/* # safety net; don't remove
+   - node # safety net; don't remove
+
+before_install:
+  - npm i -g npm@latest
+
 script:
   - npm test
+
+after_success:
+  - 'travis-after-all && npm run semantic-release'