cython (nest requirement) for mac

Author: johnpapad24

util/installation/osx/common/prerequisites.sh

@@ -58,7 +58,7 @@ brew install \
 if [ $1 == "all" ]; then
     # Fix jinja2 version because of failing build target `notebooks` on 
     # macOS System CI.
-    PIP_PACKAGES="markupsafe==2.0.1 nbformat jupyter metakernel jupyterlab jinja2==3.0"
+    PIP_PACKAGES="markupsafe==2.0.1 nbformat jupyter metakernel jupyterlab jinja2==3.0 cython"
     # Don't install --user: the packages should end up in the PYENV_ROOT directory
     python3.9 -m pip install $PIP_PACKAGES
     brew install \