Using C# 11

Author: jeremydmiller

src/Oakton/Oakton.csproj

@@ -7,6 +7,7 @@
         <TargetFrameworks>net6.0;net7.0;net8.0;net9.0</TargetFrameworks>
         <DebugType>portable</DebugType>
         <AssemblyName>Oakton</AssemblyName>
+        <LangVersion>11.0</LangVersion>
         <OutputType>Library</OutputType>
         <PackageId>Oakton</PackageId>
         <PackageTags>Command Line Parsing</PackageTags>