Updated copyright notice

Author: jstedfast

MimeKit/Properties/AssemblyInfo.cs

@@ -35,7 +35,7 @@
 [assembly: AssemblyConfiguration ("")]
 [assembly: AssemblyCompany (".NET Foundation")]
 [assembly: AssemblyProduct ("MimeKit")]
-[assembly: AssemblyCopyright ("Copyright © 2013-2024 .NET Foundation and Contributors")]
+[assembly: AssemblyCopyright ("Copyright © 2013-2025 .NET Foundation and Contributors")]
 [assembly: AssemblyTrademark (".NET Foundation")]
 [assembly: AssemblyCulture ("")]