Bump BenchmarkDotNet from 0.13.8 to 0.13.9 (#77)

Bumps [BenchmarkDotNet](https://github.com/dotnet/BenchmarkDotNet) from 0.13.8 to 0.13.9.
- [Release notes](https://github.com/dotnet/BenchmarkDotNet/releases)
- [Commits](dotnet/BenchmarkDotNet@v0.13.8...v0.13.9)

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

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

Akade.IndexedSet.Benchmarks/Akade.IndexedSet.Benchmarks.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
@@ -8,7 +8,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="BenchmarkDotNet" Version="0.13.8" />
+    <PackageReference Include="BenchmarkDotNet" Version="0.13.9" />
     <PackageReference Include="Bogus" Version="34.0.2" />
     <PackageReference Include="Fastenshtein" Version="1.0.0.8" />
   </ItemGroup>