update appveyor.yml

add config for nuget deployment

Author: JohnTheGr8

appveyor.yml

@@ -31,4 +31,12 @@ artifacts:
 - path: 'Output\Packages\Flow-Launcher-*.zip'
   name: Zip
 - path: 'Output\Release\Flow.Launcher.Plugin.*.nupkg'
-  name: Plugin nupkg
+  name: Plugin nupkg
+
+deploy:
+  provider: NuGet
+  artifact: /.*\.nupkg/
+  api_key:
+    secure: n80IeWR3pN81p0w4uXq4mO0TdTXoJSHHFL+yTB9YBJ0Wni2DjZGYwOFdaWzW4hRi
+  on:
+    branch: master