fix(travis): fixed trusty being used instead of xential

.travis.yml

@@ -1,8 +1,7 @@
-language: bash node_js
+
+language: node_js
 dist: xenial
-sudo: required
-node_js:
-  - 10
+
 before_script:
     - curl -L "https://storage.googleapis.com/google-code-archive-downloads/v2/code.google.com/shunit2/shunit2-2.1.6.tgz" | tar zx
 install:
@@ -42,4 +41,4 @@ jobs:
     - # stage name not required
       script: bash tests/tests_ts3server.sh
     - # stage name not required
-      script: bash tests/tests_shellcheck.sh
+      script: bash tests/tests_shellcheck.sh