Fix apikey flag (#167)

Author: rogebrd

.github/workflows/nuget_upload.yml

@@ -23,4 +23,4 @@ jobs:
       - name: Pack
         run: nuget pack dropbox-sdk-dotnet\Dropbox.Api\Dropbox.Api.nuspec
       - name: Publish
-        run: nuget push *.nupkg -ApiKey=${{ secrets.NUGET_TOKEN }}
+        run: nuget push *.nupkg --ApiKey ${{ secrets.NUGET_TOKEN }}