clib: Add Unlicense

clib.json

@@ -4,6 +4,6 @@
   "repo": "Immediate-Mode-UI/Nuklear",
   "description": "A small ANSI C gui toolkit",
   "keywords": ["gl", "ui", "toolkit"],
-  "license": "MIT",
+  "license": "MIT, Unlicense",
   "src": ["nuklear.h"]
 }