Update .travis.yml

.travis.yml

@@ -1,28 +1,26 @@
 language: cpp
+os: linux
 dist: xenial
 
-matrix:
-  include:
-    - os: linux
 addons:
   apt:
     sources:
       - ubuntu-toolchain-r-test
     packages:
       - g++-7
+      - qt5-qmake
+      - libqt5test5
+
+matrix:
+  include:
+    - compiler: gcc
       env:
         - MATRIX_EVAL="CC=gcc-7 && CXX=g++-7"
-
-    - os: linux
-      compiler: clang
+    - compiler: clang
 
 before_install:
     - eval "${MATRIX_EVAL}"
 
-install:
-  - sudo apt-get update
-  - sudo apt-get install qt5-qmake libqt5test5
-
 script:
   - qmake -v
   - cd ./build