docs: state that we are production ready.

Author: agentzh

README.markdown

@@ -6,9 +6,7 @@ lua-resty-upload - Streaming reader and parser for HTTP file uploading based on
 Status
 ======
 
-This library is considered experimental and still under active development.
-
-The API is still in flux and may change without notice.
+This library is considered production ready.
 
 Description
 ===========