Add undefined case for Encode enum

Author: alcaeus

src/Builder/Type/Encode.php

@@ -37,4 +37,9 @@ enum Encode
      * Specific for $group stage
      */
     case Group;
+
+    /**
+     * Default case used in the interface; implementing classes are expected to override this value
+     */
+    case Undefined;
 }

src/Builder/Type/OperatorInterface.php

@@ -10,7 +10,7 @@
 interface OperatorInterface
 {
     /** To be overridden by implementing classes */
-    public const ENCODE = Encode::Single;
+    public const ENCODE = Encode::Undefined;
 
     public function getOperator(): string;
 }