[BUG] Elastic.Serilog.Sinks/README.md is outdated

[milostns]

I was trying out your nuget package (currently latest version 8.6.1) for Serilog with the example provided at: https://www.nuget.org/packages/Elastic.Serilog.Sinks

I wouldn't compile because there is no ConcurrentConsumers property anymore in the BufferOptions class.

So I guess following line should be updated in the docs: https://github.com/elastic/ecs-dotnet/blob/eac06c3df532d33c1889cca7dca388216c945dc4/src/Elastic.Serilog.Sinks/README.md?plain=1#L28

Also a small typo how wer are communicating on this line: https://github.com/elastic/ecs-dotnet/blob/eac06c3df532d33c1889cca7dca388216c945dc4/src/Elastic.Serilog.Sinks/README.md?plain=1#L43