message: Wanrt to use Visual Studio 2017 in appveyor 3
diff: @@ -20,7 +20,7 @@ build_script:
  - mkdir build
  - cd build
  - cmake --version
  - - cmake C:\Repos\source -G "Visual Studio 16 2019%arch%"
  + - cmake C:\Repos\source -G "Visual Studio 16.7 2019%arch%"
  # - cmake C:\Repos\source -G "Visual Studio 15 2017%arch%"
  - cmake --build . --config "Release"
  