Fix appveyor to actually build and run tests

Author: quicknir

appveyor.yml

@@ -11,7 +11,9 @@ environment:
       CONFIG: Release
 
 build_script:
-  - cmake "-G%GENERATOR%" -H. -B_builds -DENABLE_TESTING=1
+  - vcpkg install catch2
+  - ps: cd test
+  - cmake -DCMAKE_TOOLCHAIN_FILE=c:/tools/vcpkg/scripts/buildsystems/vcpkg.cmake "-G%GENERATOR%" -H. -B_builds -DENABLE_TESTING=1
   - cmake --build _builds --config "%CONFIG%"
 
 test_script: