Fixing the build.

Author: gfraiteur

src/PostSharp.Engineering.BuildTools/Dependencies/Definitions/PostSharpDependencies.V2024_1.cs

@@ -4,6 +4,7 @@
 using PostSharp.Engineering.BuildTools.ContinuousIntegration;
 using PostSharp.Engineering.BuildTools.ContinuousIntegration.Model;
 using PostSharp.Engineering.BuildTools.Dependencies.Model;
+using System;
 
 namespace PostSharp.Engineering.BuildTools.Dependencies.Definitions;