Update setup.py

Author: john-maidbot

setup.py

@@ -14,7 +14,7 @@
       install_requires=[
         'numpy>=1.18.1',
         'scipy',
-        'Cython>=0.29,<=0.29.15',
+        'Cython>=0.29.14,<=0.3.0',
         'matplotlib'],
       description="Generate STL files from numpy arrays and text",
       author='Tristan Hearn',