Bump BenchmarkDotNet from 0.14.0 to 0.15.8 (#58)

---
updated-dependencies:
- dependency-name: BenchmarkDotNet
  dependency-version: 0.15.8
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: all-dependencies
...

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

Author: dependabot[bot]

tests/Shortcodes.Benchmarks/Shortcodes.Benchmarks.csproj

@@ -14,7 +14,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="BenchmarkDotNet" Version="0.14.0" />
+    <PackageReference Include="BenchmarkDotNet" Version="0.15.8" />
   </ItemGroup>
 
 </Project>