Update Travis CI configuration according to github.com/atom/ci

Author: zargony

.travis.yml

@@ -1,14 +1,28 @@
-os:
-  - linux
-  - osx
 language: generic
+
 env:
   global:
     - APM_TEST_PACKAGES=""
     - ATOM_LINT_WITH_BUNDLED_NODE="true"
+
   matrix:
     - ATOM_CHANNEL=stable
     - ATOM_CHANNEL=beta
-install: ''
+
+os:
+  - linux
+  - osx
+
+dist: trusty
+
+sudo: false
+
+addons:
+  apt:
+    sources:
+    - ubuntu-toolchain-r-test
+    packages:
+    - g++-6
+
 script:
   - curl -s https://raw.githubusercontent.com/atom/ci/master/build-package.sh | sh