Update dependency Soenneker.Extensions.String to 3.0.521 (#129)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

src/Soenneker.Excel.Util.csproj

@@ -45,7 +45,7 @@
         <PackageReference Include="ClosedXML" Version="0.105.0" />
         <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="9.0.5" />
         <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="9.0.5" />
-        <PackageReference Include="Soenneker.Extensions.String" Version="3.0.520" />
+        <PackageReference Include="Soenneker.Extensions.String" Version="3.0.521" />
         <PackageReference Include="Soenneker.Extensions.Type" Version="3.0.602" />
     </ItemGroup>
 </Project>