Development flow fails in python 3.9

[fdlk]

How to Reproduce

create a virtualenv with python 3.9, activate it and run a pip install

Expected behavior

it works

Observed behavior

Installation of ruamel.yaml errors:

Building wheels for collected packages: ruamel.yaml
  Building wheel for ruamel.yaml (setup.py) ... error
  ERROR: Command errored out with exit status 1:
   command: /Users/fkelpin/git/molgenis-tools-commander/env39/bin/python -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/private/var/folders/8f/00bjc6cs4s75rz7xhzwp4rsm0000gn/T/pip-install-pr4zpn0z/ruamel-yaml/setup.py'"'"'; __file__='"'"'/private/var/folders/8f/00bjc6cs4s75rz7xhzwp4rsm0000gn/T/pip-install-pr4zpn0z/ruamel-yaml/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' bdist_wheel -d /private/var/folders/8f/00bjc6cs4s75rz7xhzwp4rsm0000gn/T/pip-wheel-dgdzh9fc
       cwd: /private/var/folders/8f/00bjc6cs4s75rz7xhzwp4rsm0000gn/T/pip-install-pr4zpn0z/ruamel-yaml/

[tommydeboer]

@fdlk I believe this has been fixed now with the updated dependency