Comment 6 for bug 1967945

https://logserver.rdoproject.org/95/40195/3/check/periodic-tripleo-ci-build-containers-centos-9-push-master/e798e3e/job-output.txt

from here,
I am able to reproduce the issue on centos-9 container image
dnf install git-core
git clone https://opendev.org/openstack/tripleo-common
python -m venv repr
source repr/bin/activate
cd tripleo-common/
pip install -r requirements.txt -c https://raw.githubusercontent.com/openstack/requirements/master/upper-constraints.txt -i http://mirror.regionone.vexxhost-nodepool-tripleo.rdoproject.org/pypi/simple --trusted-host mirror.regionone.vexxhost-nodepool-tripleo.rdoproject.org

```
repr) [root@3dd84536401a tripleo-common]# pip install -r requirements.txt -c https://raw.githubusercontent.com/openstack/requirements/master/upper-constraints.txt -i http://mirror.regionone.vexxhost-nodepool-tripleo.rdoproject.org/pypi/simple --trusted-host mirror.regionone.vexxhost-nodepool-tripleo.rdoproject.org
Looking in indexes: http://mirror.regionone.vexxhost-nodepool-tripleo.rdoproject.org/pypi/simple
Collecting pbr!=2.1.0,>=2.0.0
  Downloading http://mirror.regionone.vexxhost-nodepool-tripleo.rdoproject.org/pypifiles/packages/5a/f0/28b2d5398ed905ce67045670e076c8dfa23ea54c19f2a8e3ac36e8153e1d/pbr-5.8.1-py2.py3-none-any.whl (113 kB)
     |████████████████████████████████| 113 kB 178 kB/s
Collecting GitPython>=1.0.1
  Downloading http://mirror.regionone.vexxhost-nodepool-tripleo.rdoproject.org/pypifiles/packages/fd/05/4b2e29f82f40d3add50956bdb9c868b3608381810b630ea439bb588f558d/GitPython-3.1.24-py3-none-any.whl (180 kB)
     |████████████████████████████████| 180 kB 27.7 MB/s
ERROR: Cannot install python-heatclient>=1.10.0 because these package versions have conflicting dependencies.

The conflict is caused by:
    The user requested python-heatclient>=1.10.0
    The user requested (constraint) python-heatclient===2.5.1

To fix this you could try to:
1. loosen the range of package versions you've specified
2. remove package versions to allow pip attempt to solve the dependency conflict

ERROR: ResolutionImpossible: for help visit https://pip.pypa.io/en/latest/user_guide/#fixing-conflicting-dependencies
WARNING: You are using pip version 21.2.3; however, version 21.3.1 is available.
You should consider upgrading via the '/repr/bin/python3 -m pip install --upgrade pip' command.