Bump pycparser upper version bound

Author: douglas-raillard-arm

setup.py

@@ -21,7 +21,7 @@
       python_requires="~=3.8",
       install_requires=[
           "ply>=3.4",
-          "pycparser>=2.18,<=2.20",
+          "pycparser~=2.21",
           ],
 
       author="Andreas Kloeckner",