Add license file

LICENSE

@@ -0,0 +1,24 @@
+API Test Base License
+=====================
+
+Copyright (C) 2023-2024 Zheng Wang. All rights reserved.
+
+This software is provided "as is", without any express or implied warranty. In no event shall the
+author be liable for any claim, damages or other liability, whether in an action of contract, tort
+or otherwise, arising from, out of or in connection with this software or the use of this software.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software, to
+use this software for any purpose, including commercial purpose, and to redistribute it, provided
+that the following conditions are met:
+
+1. All redistributions of this software must retain all copyright notices that are currently in
+   place, and this list of conditions without modification.
+
+2. The origin of this software must not be misrepresented; you must not claim that you wrote this
+   software.
+
+3. You must not sell this software or charge money to the recipient of this software's
+   redistribution.
+
+Zheng Wang
+https://apitestbase.io/