only pin mandatory packages

versions.cfg

@@ -3,87 +3,5 @@ setuptools = 44.1.1
 zc.buildout = 2.13.3
 # python 2 ...
 traitlets = 4.3.2
-
 # misc
-ecreall.helpers.testing = 1.7
-ecreall.helpers.upgrade = 1.4
-ipdb = 0.13.9
-ipython = 5.10.0
-isort = 4.3.21
-mccabe = 0.6.1
-plone.formwidget.masterselect = 1.7
-plone.recipe.codeanalysis = 3.0.1
-prompt-toolkit = 1.0.18
-ptyprocess = 0.7.0
-pyflakes = 2.3.1
-python-dateutil = 2.8.0
-simplegeneric = 0.8.1
-testfixtures = 6.18.3
-zipp = 1.2.0
-
-# Required by:
-# isort==4.3.21
-backports.functools-lru-cache = 1.6.4
-
-# Required by:
-# ipython==5.10.0
-backports.shutil-get-terminal-size = 1.0.0
-
-# Required by:
-# collective.contact.core==1.38.dev0
-collective.dexteritytextindexer = 2.4.0
-
-# Required by:
-# flake8==3.9.2
-# traitlets==4.3.2
-enum34 = 1.1.10
-
-# Required by:
-# flake8==3.9.2
-functools32 = 3.2.3.post2
-
-# Required by:
-# isort==4.3.21
-futures = 3.3.0
-
-# Required by:
-# traitlets==4.3.2
-ipython-genutils = 0.2.0
-
-# Required by:
-# importlib-metadata==1.3.0
-# ipython==5.10.0
-# pickleshare==0.7.5
-pathlib2 = 2.3.6
-
-# Required by:
-# check-manifest==0.41
-pep517 = 0.12.0
-
-# Required by:
-# ipython==5.10.0
-pexpect = 4.8.0
-
-# Required by:
-# ipython==5.10.0
-pickleshare = 0.7.5
-
-# Required by:
-# pathlib2==2.3.6
-scandir = 1.10.0
-
-# Required by:
-# check-manifest==0.41
-toml = 0.10.2
-
-# Required by:
-# flake8==3.9.2
-typing = 3.10.0.0
-
-# Required by:
-# collective.contact.core==1.38.dev0
-vobject = 0.9.6.1
-
-# Required by:
-# prompt-toolkit==1.0.18
-wcwidth = 0.2.5
+python-dateutil = 2.8.0