We're no longer using the separate dotnet-format tool since it is integrated into the dotnet SDK now.
With the move to the SDK the options changed a bit so we now need to use the `whitespace` format command so we can continue using the `--folder` option: https://github.com/dotnet/format/issues/1385
To run not just whitespace but code style formatters as well we'd need a workspace context (i.e. pass the .csproj to dotnet format), but inferring that from just the changed file list is hard.