attempt workaround for Travis testing dependencies on OS X CI testing builds

.travis.yml

@@ -1,20 +1,24 @@
 sudo: true
 language: python
 
-os:
-  - linux
-  - osx
-
 env:
   - TARGET="lint"
   - TARGET="build-with-dependencies"
 
-before_script:
-  - pip install ufolint
-  - if [ $TRAVIS_OS_NAME = "linux" ]; then sudo apt-get -qq update; fi
-  - if [ $TRAVIS_OS_NAME = "linux" ]; then sudo apt-get install -y shellcheck; fi
-  - if [ $TRAVIS_OS_NAME = "osx" ]; then brew update; fi
-  - if [ $TRAVIS_OS_NAME = "osx" ]; then brew outdated shellcheck || brew upgrade shellcheck; fi
+matrix:
+  include:
+    - os: linux
+      sudo: required
+      before_script:
+        - pip install ufolint
+        - sudo apt-get -qq update
+        - sudo apt-get install -y shellcheck
+    - os: osx
+      before_script:
+        - brew update
+        - brew install python
+        - pip install shellcheck
+        - brew outdated shellcheck || brew upgrade shellcheck
 
 script:
   - make -j $TARGET