update composer version

Author: chopins

composer.json

@@ -4,7 +4,7 @@
     "keywords": ["ui", "php","ffi","libui"],
     "homepage": "http://toknot.com",
     "license": "BSD-3-Clause",
-    "version" : "0.1",
+    "version" : "0.2.1",
     "authors": [
         {
             "name": "Szopen Xiao",