[release/3.1] Update dependencies from dotnet/core-setup (#26565)
* Update dependencies from https://github.com/dotnet/core-setup build
20190905.31
- Microsoft.NETCore.App - 3.1.0-preview1.19455.31
* Update dependencies from https://github.com/dotnet/core-setup build
20190907.3
- Microsoft.NETCore.App - 3.1.0-preview1.19457.3
* Update dependencies from https://github.com/dotnet/core-setup build
20190907.10
- Microsoft.NETCore.App - 3.1.0-preview1.19457.10
* Update dependencies from https://github.com/dotnet/core-setup build
20190908.7
- Microsoft.NETCore.App - 3.1.0-preview1.19458.7