[release/3.0] Update dependencies from dotnet/arcade (#26114)

[release/3.0] Update dependencies from dotnet/arcade (#26114)

* Update dependencies from https://github.com/dotnet/arcade build 20190809.8

- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19409.8
- Microsoft.DotNet.Build.Tasks.Feed - 2.2.0-beta.19409.8
- Microsoft.DotNet.Build.Tasks.Packaging - 1.0.0-beta.19409.8
- Microsoft.DotNet.Helix.Sdk - 2.0.0-beta.19409.8

* Update dependencies from https://github.com/dotnet/arcade build 20190810.2

- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19410.2
- Microsoft.DotNet.Build.Tasks.Feed - 2.2.0-beta.19410.2
- Microsoft.DotNet.Build.Tasks.Packaging - 1.0.0-beta.19410.2
- Microsoft.DotNet.Helix.Sdk - 2.0.0-beta.19410.2