appveyor: switch to Visual Studio 2019

nihtest needs python 3.9+ and the 2017 image only provides up to 3.8

appveyor.yml

@@ -1,67 +1,67 @@
 os:
-- Visual Studio 2017
+- Visual Studio 2019
 
 environment:
   PATH: C:\Python38-x64\Scripts;C:\Python38-arm\Scripts;$(PATH)
   matrix:
-    - GENERATOR: "Visual Studio 15 2017 Win64"
+    - GENERATOR: "Visual Studio 16 2019 Win64"
       TRIPLET: x64-windows
       CMAKE_OPTS: "-DBUILD_SHARED_LIBS=off"
       CMAKE_CONFIG: Release
       RUN_TESTS: yes
-      TOXENV: py38
-#    - GENERATOR: "Visual Studio 15 2017 Win64"
+      TOXENV: py311
+#    - GENERATOR: "Visual Studio 16 2019 Win64"
 #      TRIPLET: x64-windows
 #      CMAKE_OPTS: "-DBUILD_SHARED_LIBS=off"
 #      CMAKE_CONFIG: Debug
 #      RUN_TESTS: yes
-    - GENERATOR: "Visual Studio 15 2017 Win64"
+    - GENERATOR: "Visual Studio 16 2019 Win64"
       TRIPLET: x64-uwp
       CMAKE_OPTS: "-DCMAKE_SYSTEM_NAME=WindowsStore -DCMAKE_SYSTEM_VERSION=10.0"
       CMAKE_CONFIG: Release
       RUN_TESTS: no
-      TOXENV: py38
-    - GENERATOR: "Visual Studio 15 2017"
+      TOXENV: py311
+    - GENERATOR: "Visual Studio 16 2019"
       TRIPLET: x86-windows
       CMAKE_OPTS: "-DBUILD_SHARED_LIBS=off"
       CMAKE_CONFIG: Release
       RUN_TESTS: yes
-      TOXENV: py38
-#    - GENERATOR: "Visual Studio 15 2017"
+      TOXENV: py311
+#    - GENERATOR: "Visual Studio 16 2019"
 #      TRIPLET: x86-windows
 #      CMAKE_OPTS: "-DBUILD_SHARED_LIBS=off"
 #      CMAKE_CONFIG: Debug
 #      RUN_TESTS: yes
-    - GENERATOR: "Visual Studio 15 2017"
+    - GENERATOR: "Visual Studio 16 2019"
       TRIPLET: x86-uwp
       CMAKE_OPTS: "-DCMAKE_SYSTEM_NAME=WindowsStore -DCMAKE_SYSTEM_VERSION=10.0"
       CMAKE_CONFIG: Release
       RUN_TESTS: no
-      TOXENV: py38
-    - GENERATOR: "Visual Studio 15 2017 ARM"
+      TOXENV: py311
+    - GENERATOR: "Visual Studio 16 2019 ARM"
       TRIPLET: arm-windows
       CMAKE_OPTS: "-DENABLE_OPENSSL=off"
       CMAKE_CONFIG: Release
       RUN_TESTS: no
-      TOXENV: py38
-    - GENERATOR: "Visual Studio 15 2017 ARM"
+      TOXENV: py311
+    - GENERATOR: "Visual Studio 16 2019 ARM"
       TRIPLET: arm-uwp
       CMAKE_OPTS: "-DCMAKE_SYSTEM_NAME=WindowsStore -DCMAKE_SYSTEM_VERSION=10.0 -DENABLE_OPENSSL=off"
       CMAKE_CONFIG: Release
       RUN_TESTS: no
-      TOXENV: py38
-    - GENERATOR: "Visual Studio 15 2017"
+      TOXENV: py311
+    - GENERATOR: "Visual Studio 16 2019"
       TRIPLET: arm64-windows
       CMAKE_OPTS: "-AARM64 -DENABLE_OPENSSL=off"
       CMAKE_CONFIG: Release
       RUN_TESTS: no
-      TOXENV: py38
-    - GENERATOR: "Visual Studio 15 2017"
+      TOXENV: py311
+    - GENERATOR: "Visual Studio 16 2019"
       TRIPLET: arm64-uwp
       CMAKE_OPTS: "-AARM64 -DCMAKE_SYSTEM_NAME=WindowsStore -DCMAKE_SYSTEM_VERSION=10.0 -DENABLE_OPENSSL=off"
       CMAKE_CONFIG: Release
       RUN_TESTS: no
-      TOXENV: py38
+      TOXENV: py311
 
 before_build:
   cmd: >-