Reduced number of configuration

.appveyor.yml

@@ -32,6 +32,10 @@ matrix:
       configuration: Debug
     - image: Visual Studio 2017
       platform: x86
+    - image: Visual Studio 2017
+      configuration: Debug
+    - image: Visual Studio 2019
+      platform: x86
 
 before_build:
   - ps: |