Fixed release pipeline (#515)

Author: yaira2

azure-pipelines.yml

@@ -23,7 +23,7 @@ steps:
     platform: 'x86'
     solution: '**/*.wapproj'
     configuration: '$(buildConfiguration)'
-    msbuildArguments: '/t:build;_GenerateAppxPackage /p:Configuration=Release;Platform="$(buildPlatform)";AppxBundle=Always;AppxBundlePlatforms="$(buildPlatform)"'
+    msbuildArguments: '/t:build;_GenerateAppxPackage /p:Configuration=Release;Platform="$(buildPlatform)";AppxBundle=Always;AppxBundlePlatforms="$(buildPlatform)";/p:UapAppxPackageBuildMode=StoreUpload'
 
 - task: store-publish@0
   inputs: