Bump BenchmarkDotNet from 0.12.1 to 0.13.0 (#1590)

Bumps [BenchmarkDotNet](https://github.com/dotnet/BenchmarkDotNet) from 0.12.1 to 0.13.0.
- [Release notes](https://github.com/dotnet/BenchmarkDotNet/releases)
- [Commits](dotnet/BenchmarkDotNet@v0.12.1...v0.13.0)

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benchmarks/RestSharp.Benchmarks/RestSharp.Benchmarks.csproj

@@ -7,7 +7,7 @@
 
     <ItemGroup>
       <PackageReference Include="AutoFixture" Version="4.17.0" />
-      <PackageReference Include="BenchmarkDotNet" Version="0.12.1" />
+      <PackageReference Include="BenchmarkDotNet" Version="0.13.0" />
       <PackageReference Include="Utf8Json" Version="1.3.7" />
     </ItemGroup>