Update Microsoft.Extensions.DependencyInjection version and add darc subscription

The Microsoft.Extensions.DependencyInjection version in this repo is still on Preview 2:
https://github.com/dotnet/format/blob/a90970ae7b7bcc1b2e41165767bc077a02fb9485/eng/Versions.props#L18

This causes issues for source-build because we build with the newest versions of every package. Upgrading Microsoft.Extensions.DependencyInjection introduces a breaking change with the `ILogger` API. We have to carry a patch for this change in source-build: https://github.com/dotnet/installer/pull/13844/files#diff-71d36e085118e1d7e0b16400b715bf3e12375113d08cfaa1c815cb8bc0748131

If possible, there should be an automatic dependency flow from dotnet/runtime to dotnet/format for Microsoft.Extensions.DependencyInjection, so the package version gets automatically updated.