Update Appveyor config file

Not exactly sure if this will be enough to make it run. There seems to
have been substantial changes since we last looked at this. I may just
stop using this service and move the windows builds to github.

Author: php1ic

appveyor.yml

@@ -13,8 +13,8 @@ skip_commits:
     - scripts/*
 
 os:
-  - Visual Studio 2017
   - Visual Studio 2019
+  - Visual Studio 2022
 
 install:
   - git submodule init