revert enum class

src/Pieces/Color.cpp

@@ -31,8 +31,8 @@ const Color& getColor(ColorEnum color) {
 }
 
 void setNextPieceColor(ColorEnum& color) {
-    if (color == ColorEnum::GREEN)
-        color = ColorEnum::PURPLE;
+    if (color == GREEN)
+        color = PURPLE;
     else
         color = ColorEnum(color + 1);
 }