Fix the warning problem.

ci-requirements.txt

@@ -6,7 +6,7 @@ wheel
 # name to be created so that we can have both foo.py and _foo.so
 # at the same time.
 # 0.28b1 has been tagged but not uploaded to PyPI
--e git+https://github.com/cython/cython.git@0.28b1#egg=cython
+-e git+https://github.com/cython/cython.git@bfa76156a76841b03a0e2821fd7cadbd2eeefcab#egg=cython
 
 # Python 3.7b1 requires this.
 greenlet>=0.4.13 ; platform_python_implementation == "CPython"

scripts/releases/geventrel.sh

@@ -35,12 +35,10 @@ echo cloning $BASE
 git clone $BASE gevent
 cd ./gevent
 pip install -U pip
-pip install -U setuptools cython greenlet cffi
+pip install -U setuptools greenlet cffi
 pip install -U wheel
 # We may need different versions of deps depending on the
 # version of python; that's captured in this file.
-# we still need to upgrade cython first, though
-# because we can get kwargs errors otherwise
 pip install -U -r dev-requirements.txt
 python ./setup.py sdist bdist_wheel
 cp dist/*whl /tmp/gevent/