Update main.yml

Author: ethomson

.github/workflows/main.yml

@@ -67,13 +67,13 @@ jobs:
           skip_ssh_tests: true
         - # Windows Visual Studio amd64
           os: windows-latest
-          cmake_generator: Visual Studio 15 2017
+          cmake_generator: Visual Studio 16 2019
           cmake_options: -A Win32 -DMSVC_CRTDBG=ON -DDEPRECATE_HARD=ON -DUSE_SHA1=HTTPS
           skip_ssh_tests: true
           skip_negotiate_tests: true
         - # Windows Visual Studio amd64
           os: windows-latest
-          cmake_generator: Visual Studio 15 2017
+          cmake_generator: Visual Studio 16 2019
           cmake_options: -A x64 -DMSVC_CRTDBG=ON -DDEPRECATE_HARD=ON
           skip_ssh_tests: true
           skip_negotiate_tests: true