Update benchmark file

[metalgearsloth]

I was reminded that https://github.com/aaubry/YamlDotNet/tree/master/YamlDotNet.Benchmark/Resources is still using one of our old yaml files. This is now one of our smaller yaml files and we have much larger ones in our game now with fland.yml being the largest https://github.com/space-wizards/space-station-14/tree/master/Resources/Maps (currently 3x the size of saltern.yml).