Merge pull request #7781 from ThomasWaldmann/cy029-1.2

require cython <3 for now

requirements.d/development.txt

@@ -8,7 +8,7 @@ pytest
 pytest-xdist
 pytest-cov
 pytest-benchmark
-Cython
+Cython <3
 twine
 python-dateutil
 pre-commit