requirements.lock.txt: use the latest cython release

requirements.d/development.lock.txt

@@ -7,5 +7,5 @@ pytest==6.1.2; python_version < '3.10'
 pytest-xdist==2.2.1
 pytest-cov==2.12.1
 pytest-benchmark==3.4.1
-Cython==0.29.27
+Cython==0.29.30
 twine==1.15.0