Update to C# 14.0

Co-authored-by: BenjaminMichaelis <22186029+BenjaminMichaelis@users.noreply.github.com>

Author: Copilot

Directory.Build.props

@@ -16,7 +16,7 @@
 	<PackageReadmeFile>README.md</PackageReadmeFile>
   </PropertyGroup>
   <PropertyGroup>
-  	<LangVersion>12.0</LangVersion>
+  	<LangVersion>14.0</LangVersion>
   	<ImplicitUsings>true</ImplicitUsings>
   	<Nullable>enable</Nullable>
   </PropertyGroup>