Try to fix the build

.travis.yml

@@ -23,7 +23,7 @@ matrix:
     - os: windows
       before_install:
         - choco install python3
-        - export PATH="/c/Python38:/c/Python38/Scripts:$PATH"
+        - export PATH="/c/Python39:/c/Python39/Scripts:$PATH"
         - wget http://anki3d.org/VulkanSDKLib.zip
         - unzip VulkanSDKLib.zip -d vulkansdk
         - export VULKAN_SDK=$TRAVIS_BUILD_DIR/vulkansdk