message: travis.yml: switched to using xcode11.1 image
diff: @@ -26,11 +26,13 @@ matrix:
  env:
  - CONFIG=Debug
  - os: osx
  + osx_image: xcode11.1
  compiler: clang
  env:
  - CONFIG=Debug
  - IOS=false
  - os: osx
  + osx_image: xcode11.1
  compiler: clang
  env:
  - CONFIG=Debug
  @@ -40,11 +42,13 @@ matrix:
  env:
  - CONFIG=Release
  - os: osx
  + osx_image: xcode11.1
  compiler: clang
  env:
  - CONFIG=Release
  - IOS=false
  - os: osx
  + osx_image: xcode11.1
  compiler: clang
  env:
  - CONFIG=Release
  