Add Chiplotle3

The legacy Chiplotle is less useful on modern (Python 3.x) systems, added the forked / updated version.

README.md

@@ -69,6 +69,7 @@ A curated list of code and resources for computer-controlled drawing machines an
 HPGL is a serial/text-based protocol used by most old pen plotters, and even many new vinyl cutters.
 
 - [Chiplotle](https://github.com/drepetto/chiplotle) - Python library for generating HPGL and interfacing with serial plotters.
+  - [Chiplotle3](https://github.com/cyprienh/chiplotle3) - Chiplotle fork updated for Python 3.x compatibility.
 - [HPGL Reference Guide](https://www.isoplotec.co.jp/HPGL/eHPGL.htm) - HTML-based HPGL Reference.
 - [HP 7475A Interfacing and Programming Manual](https://archive.org/details/HP7475AInterfacingandProgrammingManual) - Scanned PDF manual that contains a full HPGL reference.
 - [djipco/hpgl](https://github.com/djipco/hpgl) - A Node.js library to communicate with HPGL-compatible plotters and printers.