WIP Restrict install cffi in test_requirements.txt [cd build]

Author: thomasjpfan

test_requirements.txt

@@ -7,7 +7,7 @@ pytz==2021.3
 pytest-cov==3.0.0
 pickle5; python_version == '3.7' and platform_python_implementation != 'PyPy'
 # for numpy.random.test.test_extending
-cffi; python_version <= '3.10'
+cffi; python_version < '3.10'
 # For testing types. Notes on the restrictions:
 # - Mypy relies on C API features not present in PyPy
 mypy==0.910; platform_python_implementation != "PyPy"