Swift 6.4 migration and exhancements (#1)

This PR contains the work done to update the library and the attached example project to use the Swift 6.4 computer as a minimum supported version and also, to use the latest features introduced in it.

Reviewed-on: #1
Co-authored-by: Javier Cicchelli <javier@rock-n-code.com>

Sources/PlaydateKit/Lua/Enumerations/ClassValue.swift

@@ -1,11 +1,8 @@
 extension Lua {
-    /// A constant published on a registered class.
+    /// A class constant for `Lua.registerClass`. Wraps `lua_val`.
     public enum ClassValue {
-        /// An integer constant.
         case int(name: String, value: UInt32)
-        /// A floating-point constant.
         case float(name: String, value: Float)
-        /// A string constant.
         case string(name: String, value: String)
     }
 }