Added VS2022 job and C++20 and C++latest jobs to AppVeyor CI.

Author: Lastique

appveyor.yml

@@ -18,19 +18,24 @@ environment:
       ADDRMD: 32
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
     - TOOLSET: msvc-14.0
+      CXXSTD: 14,latest
       ADDRMD: 32,64
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
     - TOOLSET: msvc-14.1
-      CXXSTD: 14,17
+      CXXSTD: 14,17,latest
       ADDRMD: 32,64
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
     - TOOLSET: msvc-14.2
       ADDRMD: 32,64
-      CXXSTD: 14,17
+      CXXSTD: 14,17,20,latest
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+    - TOOLSET: msvc-14.3
+      ADDRMD: 32,64
+      CXXSTD: 14,17,20,latest
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2022
     - TOOLSET: clang-win
       ADDRMD: 32,64
-      CXXSTD: 14,17
+      CXXSTD: 14,17,latest
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
     - TOOLSET: gcc
       CXXSTD: 03,11,14,1z