Fix new version of click breaking old version of black.
mypy
-black==20.8b1
+black==20.8b1 # Use old version of black, because newer version is incompatible with our TF 2.4.
isort>=5.1
pytest>=3.5.0
pytest-cov
pytest-random-order
-pytest-xdist # for local tests only
+pytest-xdist
codecov
-types-dataclasses
-types-pkg_resources # for mypy check of gpflow/versions.py
+types-pkg_resources
types-tabulate
types-Deprecated
@@ -34,5 +33,7 @@ sphinx-autoapi
sphinxcontrib-bibtex
sphinx_autodoc_typehints
-# Not used directly, but at the time of this writing Jinja2 3.1.0 breaks our notebooks.
+# Not used directly, but at the time of this writing `Jinja2` 3.1.0 breaks our notebooks.
Jinja2<3.1.0
+# Not used directly, but at the time of this writing `click` 8.1.0 breaks `black` 20.8b1.
+click<8.1.0
