build: Fix the version of the nuget for .NET5

Author: NelsonBN

tests/PowerUtils.AspNetCore.ErrorHandler.Tests/PowerUtils.AspNetCore.ErrorHandler.Tests.csproj

@@ -45,7 +45,7 @@
     <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" Version="6.0.10" />
   </ItemGroup>
   <ItemGroup Condition=" '$(TargetFramework)' == 'net5.0' ">
-    <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" Version="[6.0.10]" />
+    <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" Version="[5.0.17]" />
   </ItemGroup>