Update dependency Soenneker.Utils.Delay to 3.0.21

Author: renovate[bot]

src/Soenneker.Utils.BackgroundQueue.csproj

@@ -43,6 +43,6 @@
         <PackageReference Include="Soenneker.Extensions.MethodInfo" Version="3.0.345" />
         <PackageReference Include="Soenneker.Extensions.Task" Version="3.0.102" />
         <PackageReference Include="Soenneker.Extensions.ValueTask" Version="3.0.92" />
-        <PackageReference Include="Soenneker.Utils.Delay" Version="3.0.20" />
+        <PackageReference Include="Soenneker.Utils.Delay" Version="3.0.21" />
     </ItemGroup>
 </Project>