Attempted fix of Linux travis build check

.travis.yml

@@ -5,7 +5,7 @@ cache: ccache
 matrix:
   include:
     - os: linux
-      dist: trusty
+      dist: bionic
       env: TARGET="linux64"
       compiler: gcc
       cache:
@@ -40,8 +40,7 @@ install:
       gstreamer1.0-plugins-base-apps gstreamer1.0-plugins-good
       gstreamer1.0-plugins-ugly gstreamer1.0-x gstreamer1.0-tools;
       sudo apt-get install qtmultimedia5-dev;
-      wget http://mirrors.kernel.org/ubuntu/pool/main/c/ccache/ccache_3.3.4-1_amd64.deb;
-      sudo dpkg -i ccache_3.3.4-1_amd64.deb;
+      sudo apt-get install ccache
     fi
 
   - if [ "$TARGET" == "osx" ]; then