[release/3.0] Update dependencies from dotnet/arcade (#26205)
* Update dependencies from https://github.com/dotnet/arcade build
20190815.27
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19415.27
- Microsoft.DotNet.Build.Tasks.Feed - 2.2.0-beta.19415.27
- Microsoft.DotNet.Build.Tasks.Packaging - 1.0.0-beta.19415.27
- Microsoft.DotNet.Helix.Sdk - 2.0.0-beta.19415.27
* Update dependencies from https://github.com/dotnet/arcade build
20190816.16
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19416.16
- Microsoft.DotNet.Build.Tasks.Feed - 2.2.0-beta.19416.16
- Microsoft.DotNet.Build.Tasks.Packaging - 1.0.0-beta.19416.16
- Microsoft.DotNet.Helix.Sdk - 2.0.0-beta.19416.16