Update README.md

Add PLY project

Author: camarajm

README.md

@@ -191,6 +191,7 @@ A curated list of awesome Python frameworks, libraries and software. Inspired by
     * [python-slugify](https://github.com/un33k/python-slugify) - A Python slugify library that translates unicode to ASCII.
     * [unicode-slugify](https://github.com/mozilla/unicode-slugify) - A slugifier that generates unicode slugs with Django as a dependency.
 * Parser
+    * [PLY](http://www.dabeaz.com/ply/) - Implementation of lex and yacc parsing tools for Python
     * [phonenumbers](https://github.com/daviddrysdale/python-phonenumbers) - Parsing, formatting, storing and validating international phone numbers.
     * [python-user-agents](https://github.com/selwin/python-user-agents) - Browser user agent parser.
     * [sqlparse](https://sqlparse.readthedocs.org/) - A non-validating SQL parser.