[Builds] AppVeyor: use Visual Studio 2022 image (#1911)

We want to use latest SDK and ability to run against net6.0 tests. It looks like the pool issue with VS 2022 has been resolved on the AppVeyor side so: yay! That solves everything cleanly with no installs.

appveyor.yml

@@ -1,4 +1,4 @@
-image: Visual Studio 2019
+image: Visual Studio 2022
 
 skip_branch_with_pr: true
 skip_tags: true
@@ -35,7 +35,7 @@ init:
   - git config --global core.autocrlf input
   - SET PATH=%POSTGRES_PATH%\bin;%MYSQL_PATH%\bin;%PATH%
   - net start MSSQL$SQL2019
-
+    
 nuget:
   disable_publish_on_pr: true