update travis.yml

.travis.yml

@@ -4,7 +4,7 @@ matrix:
   include:
     # works on Precise and Trusty
     - os: linux
-    - dist: xenial
+    - dist: bionec
       compiler: clang
       addons:
         apt:
@@ -20,7 +20,7 @@ before_install:
  - gem install bundler
  - curl -sSL https://sh.rustup.rs | sh -s -- -y --default-toolchain=nightly --profile=minimal
  - export PATH="$PATH:$HOME/.cargo/bin"
- - sudo add-apt-repository ppa:beineri/opt-qt-5.14.2-xenial -y
+ - sudo add-apt-repository ppa:beineri/opt-qt-5.14.2-bionic -y
  - sudo apt-get update -qq
  - sudo apt-get install qt514base qt514websockets libgl1-mesa-dev
  - source /opt/qt514/bin/qt514-env.sh