Specify pyzmq version due to osbrain

[bangxiangyong]

There's some breaking happening which i painfully figured out -

• pyzmq (a dependency of osbrain) was updated few hours ago ..
• upon importing the agentMET4FOF latest version (0.4.1) , the following occurs
• ImportError: DLL load failed while importing error: The specified module could not be found.
• this problem is fixed by downgrading the pyzmq from 22.0.1 to 21.0.1

We may need to put this in the requirements.txt

[BjoernLudwigPTB]

This constraint should then go into the setup.py's section install_requires, where we should put something like pyzmq<22.0.1 after some thorough testing which is the first version, that breaks. Of course we should include a comment about the error, with a link to this issue for further investigations at later times. We did something similar for matplotlib.