AppVeyor: Deploy only if build was done under official account

Author: ge0rdi

appveyor.yml

@@ -18,6 +18,8 @@ deploy:
 - provider: GitHub
   tag: v$(APPVEYOR_BUILD_VERSION)
   release: $(APPVEYOR_BUILD_VERSION)
+  on:
+    APPVEYOR_ACCOUNT_NAME: passionate-coder
   auth_token:
     secure: 01CsOFRdj9KFb1hp/RlFK/F1UzGhzwGQfok6OoqcL1ipbOwRF//Phbdm7iaFVWIx
   prerelease: true