Merge pull request #1184 from dotnet/dependabot/nuget/Rx.NET/Source/BenchmarkDotNet-0.12.1

Bump BenchmarkDotNet from 0.12.0 to 0.12.1 in /Rx.NET/Source

Rx.NET/Source/benchmarks/Benchmarks.System.Reactive/Benchmarks.System.Reactive.csproj

@@ -21,7 +21,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="BenchmarkDotNet" Version="0.12.0" />
+    <PackageReference Include="BenchmarkDotNet" Version="0.12.1" />
     <PackageReference Include="WindowsBase" Version="4.6.1055" />
   </ItemGroup>