Fix minor typo in Readme.

README.md

@@ -26,7 +26,7 @@ If you want more control over the image or would like to do custom drawing, the
 var
   qr : TQRCode;
 begin
-  qry:= TQRCode.Create;
+  qr:= TQRCode.Create;
   try
     qr.OnPaint :=
       procedure(Width, Height : integer; BlackRects : TArray<TRect>)