Update .travis.yml

.travis.yml

@@ -1,27 +1,12 @@
-language: generic
+dist: bionic
-os: osx
+language: cpp
-matrix:
+os:
-  include:
+  - osx
-    - os: linux
+  - linux
-      env: COMPILER_NAME=gcc CXX=g++-5 CC=gcc-5
-      addons:
-        apt:
-          packages:
-            - g++-5
-          sources: &sources
-            - llvm-toolchain-precise-3.8
-            - ubuntu-toolchain-r-test
-    - os: linux
-      env: COMPILER_NAME=clang CXX=clang++-3.8 CC=clang-3.8
-      addons:
-        apt:
-          packages:
-            - clang-3.8
-          sources: *sources
-
-script: make all
 
 compiler:
   - clang
   - gcc
 
+script: make all
+