Test against VS2019 on Appveyor

appveyor.yml

@@ -4,18 +4,20 @@ configuration:
 
 environment:
   matrix:
-  - TOOLCHAIN: Msvc 2017 x86
-    GENERATOR: Visual Studio 15 2017
+  - TOOLCHAIN: Msvc 2019 x86
+    GENERATOR: Visual Studio 16 2019
+    CMAKE_ARGS: -A Win32
 
-  - TOOLCHAIN: Msvc 2017 x64
-    GENERATOR: Visual Studio 15 2017 Win64
+  - TOOLCHAIN: Msvc 2019 x64
+    GENERATOR: Visual Studio 16 2019
+    CMAKE_ARGS: -A x64
 
-  - TOOLCHAIN: Msvc 2017 x64/Ninja
+  - TOOLCHAIN: Msvc 2019 x64/Ninja
     GENERATOR: Ninja
-    VCVARS: C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Auxiliary\Build\vcvars64.bat
+    VCVARS: C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvars64.bat
 
 image:
-  - Visual Studio 2017
+  - Visual Studio 2019
 
 install:
   - cmd: pip install ninja cmake
@@ -25,7 +27,7 @@ before_build:
   - cmd: if defined VCVARS call "%VCVARS%"
   - ps: mkdir build
   - ps: cd build
-  - cmd: cmake .. -G"%GENERATOR%"
+  - cmd: cmake .. -G"%GENERATOR%" %CMAKE_ARGS%
 
 build_script:
   - cmake --build . --config %CONFIGURATION%