chore(deps): update dependency benchmarkdotnet to 0.15.6

Author: renovate[bot]

dotnet/Gherkin.Benchmarks/Gherkin.Benchmarks.csproj

@@ -9,7 +9,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="BenchmarkDotNet" Version="0.15.0" />
+    <PackageReference Include="BenchmarkDotNet" Version="0.15.6" />
     <PackageReference Include="System.Collections.Immutable" Version="8.0.0" />
     <PackageReference Include="System.Reflection.Metadata" Version="8.0.1" />
   </ItemGroup>