Travis config tweaks (#693)

* Remove sudo: false from .travis.yml

Not needed as per
https://docs.travis-ci.com/user/reference/trusty/#container-based-infrastructure

* Run linter on Node 12

Author: RyanZim

.travis.yml

@@ -1,4 +1,3 @@
-sudo: false
 language: node_js
 os:
   - linux
@@ -14,10 +13,10 @@ env: TEST_SUITE=unit
 matrix:
   exclude:
     - os: linux
-      node_js: 8
+      node_js: 12
   include:
     - os: linux
-      node_js: 8
+      node_js: 12
       env: TEST_SUITE=full-ci
 script: npm run-script $TEST_SUITE
 after_success: