Hi,

Today pip 20.3 is released[1] and jobs started failing during keystone
install in devstack with:

2020-11-30 15:14:31.117 | + inc/python:pip_install:193               : 
 sudo -H LC_ALL=en_US.UTF-8 SETUPTOOLS_USE_DISTUTILS=stdlib http_proxy=
https_proxy= no_proxy= PIP_FIND_LINKS=
SETUPTOOLS_SYS_PATH_TECHNIQUE=rewrite python3.6 -m pip install -c
/opt/stack/old/requirements/upper-constraints.txt -e
/opt/stack/old/neutron
2020-11-30 15:14:32.271 | Looking in indexes:
https://mirror.gra1.ovh.opendev.org/pypi/simple,
https://mirror.gra1.ovh.opendev.org/wheel/ubuntu-18.04-x86_64
2020-11-30 15:14:32.272 | DEPRECATION: Constraints are only allowed to
take the form of a package name and a version specifier. Other forms
were originally permitted as an accident of the implementation, but
were undocumented. The new implementation of the resolver no longer
supports these forms. A possible replacement is replacing the
constraint with a requirement.. You can find discussion regarding this
at https://github.com/pypa/pip/issues/8210.
2020-11-30 15:14:32.272 | ERROR: Links are not allowed as constraints