AppVeyor: move to VS 2022 image (#2387)

* AppVeyor: move to VS 2022 image

The update blog post (https://www.appveyor.com/updates/2023/02/24/) doesn't match the inventory (https://www.appveyor.com/docs/windows-images-software/), primarily: .NET 6 SDK which is LTS is no longer on the 2019 image which seems like an oops. Bypassing the issue for now by getting on the 2022 image.

* Okay...install both I guess

Cloud images are fun!

* bahhhhhhhhh

* 4th time's a charm

* Maybe 5th

* Force it

* 7.0.200

* trying explicitly named packages

* Splitting lines

---------

Co-authored-by: slorello89 <steve.lorello@redis.com>

appveyor.yml

@@ -6,7 +6,9 @@ init:
 
 install:
 - cmd: >-
-    choco install dotnet-sdk --version 7.0.102
+    choco install dotnet-6.0-sdk
+
+    choco install dotnet-7.0-sdk
 
     cd tests\RedisConfigs\3.0.503