Bump BenchMarkDotNet from 0.13.7 to 0.13.8

Bumps [BenchMarkDotNet](https://github.com/dotnet/BenchmarkDotNet) from 0.13.7 to 0.13.8.
- [Release notes](https://github.com/dotnet/BenchmarkDotNet/releases)
- [Commits](dotnet/BenchmarkDotNet@v0.13.7...v0.13.8)

---
updated-dependencies:
- dependency-name: BenchMarkDotNet
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

tests/Tests.ScratchPad/Tests.ScratchPad.csproj

@@ -12,6 +12,6 @@
 
   <ItemGroup>
     <PackageReference Include="System.Diagnostics.DiagnosticSource" Version="6.0.1" />
-    <PackageReference Include="BenchMarkDotNet" Version="0.13.7" />
+    <PackageReference Include="BenchMarkDotNet" Version="0.13.8" />
   </ItemGroup>
 </Project>