Bump BenchmarkDotNet from 0.13.6 to 0.13.9 (#346)

Bumps [BenchmarkDotNet](https://github.com/dotnet/BenchmarkDotNet) from 0.13.6 to 0.13.9.
- [Release notes](https://github.com/dotnet/BenchmarkDotNet/releases)
- [Commits](dotnet/BenchmarkDotNet@v0.13.6...v0.13.9)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

src/GraphQLParser.Benchmarks/GraphQLParser.Benchmarks.csproj

@@ -15,7 +15,7 @@
 
   <ItemGroup>
     <ProjectReference Include="..\GraphQLParser\GraphQLParser.csproj" />
-    <PackageReference Include="BenchmarkDotNet" Version="0.13.6" />
+    <PackageReference Include="BenchmarkDotNet" Version="0.13.9" />
   </ItemGroup>
 
 </Project>