Require Cython 3.0

Author: Matthias Koeppe

README.rst

@@ -48,6 +48,8 @@ Requirements:
   or install from source.
 - Python >= 3.9
 - pip
+- `cysignals <https://pypi.python.org/pypi/cysignals/>`_ >= 1.7
+- Cython >= 3.0
 
 Install cypari2 via the Python Package Index (PyPI) via