Bump BenchmarkDotNet from 0.13.12 to 0.15.6#9

dependabot[bot] wants to merge 1 commit intomainTimmyMC/Schema.NET:mainfrom

dependabot/nuget/Benchmarks/Schema.NET.Benchmarks/BenchmarkDotNet-0.15.6TimmyMC/Schema.NET:dependabot/nuget/Benchmarks/Schema.NET.Benchmarks/BenchmarkDotNet-0.15.6Copy head branch name to clipboard