Log Message:
py-cython: updated to 0.29.7

0.29.7:
Bugs fixed
* Crash when the shared Cython config module gets unloaded and another Cython
  module reports an exceptions.  Cython now makes sure it keeps an owned reference
  to the module.
* Resolved a C89 compilation problem when enabling the fast-gil sharing feature.
* Coverage reporting did not include the signature line of cdef functions.
* Casting a GIL-requiring function into a nogil function now issues a warning.
* Generators and coroutines were missing their return type annotation.