(build) Fixing InspectCode Problem

- Removed unnecessary using statement

Author: gep13

Source/GitHubReleaseManager/ReleaseNotesBuilder.cs

@@ -10,7 +10,6 @@ namespace GitHubReleaseManager
     using System.Collections.Generic;
     using System.Collections.ObjectModel;
     using System.Globalization;
-    using System.IO;
     using System.Linq;
     using System.Text;
     using System.Threading.Tasks;