yydecode: replace deprecated SPDX identifier

Author: leoheitmannruiz

Formula/y/yydecode.rb

@@ -3,7 +3,7 @@ class Yydecode < Formula
   homepage "https://yydecode.sourceforge.net/"
   url "https://downloads.sourceforge.net/project/yydecode/yydecode/0.2.10/yydecode-0.2.10.tar.gz"
   sha256 "bd4879643f6539770fd23d1a51dc6a91ba3de2823cf14d047a40c630b3c7ba66"
-  license "GPL-2.0"
+  license "GPL-2.0-or-later"
 
   bottle do
     rebuild 1