Merge pull request #3071 from ThomasWaldmann/exclude-cython027-1.0

exclude Cython 0.27(.0) in requirements, fixes #3066

requirements.d/development.txt

@@ -7,4 +7,4 @@ pytest
 pytest-xdist
 pytest-cov
 pytest-benchmark
-Cython
+Cython!=0.27