Add build artifacts to AppVeyor output

Author: sharwell

appveyor.yml

@@ -17,3 +17,6 @@ test_script:
 # preserve "packages" directory in the root of build folder but will reset it if packages.config is modified
 cache:
   - packages -> **\packages.config
+artifacts:
+- path: 'StyleCop.Analyzers\**\*.vsix'
+- path: 'StyleCop.Analyzers\**\*.nupkg'