message: appveyor: revert back to Visual Studio 15 2017
diff: @@ -3,21 +3,29 @@ clone_depth: 5
  # https://www.appveyor.com/docs/windows-images-software/
  environment:
  matrix:
  - # Visual Studio 2019 x64
  #- GENERATOR: -G"Visual Studio 16 2019" -A x64
  + # APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
  # BUILD_TYPE: Release
  # PYTHON: "C:\\Python39-x64"
  # # add to path otherwise Cython is not found
  # PATH: $(PYTHON)\Scripts;$(PATH)
  # PLATFORM: x64
  - # APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
  - - GENERATOR: -G Ninja
  +
  + - GENERATOR: -G"Visual Studio 15 2017 Win64"
  + APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
  BUILD_TYPE: Release
  PYTHON: "C:\\Python39-x64"
  # add to path otherwise Cython is not found
  PATH: $(PYTHON)\Scripts;$(PATH)
  PLATFORM: x64
  - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
  +
  + #- GENERATOR: Ninja
  + # BUILD_TYPE: Release
  + # PYTHON: "C:\\Python39-x64"
  + # # add to path otherwise Cython is not found
  + # PATH: $(PYTHON)\Scripts;$(PATH)
  + # PLATFORM: x64
  + # APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
  install:
  - 'systeminfo'
  