added missing token

.appveyor.yml

@@ -11,6 +11,7 @@ skip_branch_with_pr: true
 
 environment:
   vsuffix: alpha$(APPVEYOR_BUILD_NUMBER)
+  is_prerelease: true
 
 before_build:
   - cmd: cd Keyczar
@@ -43,9 +44,13 @@ deploy:
     symbol_server: https://www.myget.org/F/keyczar-dotnet-ci/symbols/api/v2/package
 
   - provider: GitHub
+
     artifact: /.*\.nupkg/           # upload all NuGet packages to release assets
+    description: 'Release description'
+    auth_token:
+      secure: JyJYSgeJYFmkaFy7Gro2dQyv/fqZwz1EzJmp2Nf99H6HUpxNR7ilA/OGPcQk0pA8
     draft: true
-    prerelease: true
+    prerelease: $(is_prerelease)
     on:
       appveyor_repo_tag: true       # deploy on tag push only
 
@@ -58,11 +63,13 @@ for:
           - /v.*-beta/
     environment:
       vsuffix: beta$(APPVEYOR_BUILD_NUMBER)
+      is_prerelease: true
   - branches:
         only:
           - /v[\d,.]*/
     configuration: Release
     environment:
       vsuffix: $(APPVEYOR_BUILD_NUMBER)
+      is_prerelease: false