Bump(pyavd): Add support for Python 3.9 in PyAVD

[ClausHolbechArista]

Change Summary

Add support for Python 3.9 in PyAVD

How to test

• Adding test coverage for python 3.9 in tox.
• Excluding a few incompatible tests for python 3.9.

Checklist

User Checklist

• N/A

Repository Checklist

• My code has been rebased from devel before I start
• I have read the CONTRIBUTING document.
• My change requires a change to the documentation and documentation have been updated accordingly.
• I have updated molecule CI testing accordingly. (check the box if not applicable)

[github-actions]

Review docs on Read the Docs

To test this pull request:

# Create virtual environment for this testing below the current directory
python -m venv test-avd-pr-4051
# Activate the virtual environment
source test-avd-pr-4051/bin/activate
# Install all requirements including PyAVD
pip install "pyavd[ansible] @ git+https://github.com/ClausHolbechArista/avd.git@bump/pyavd/support-python3.9#subdirectory=python-avd" --force
# Install Ansible collection
ansible-galaxy collection install git+https://github.com/ClausHolbechArista/avd.git#/ansible_collections/arista/avd/,bump/pyavd/support-python3.9 --force
# Optional: Install AVD examples
cd test-avd-pr-4051
ansible-playbook arista.avd.install_examples

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[ClausHolbechArista]

Tested offline by @philippebureau.

[carlbuchmann]

LGTM!

Tested with Python 3.9.18, no diffs in configs between Python 3.11 and PyAVD 4.8.0

 dc-fabrics git:(main) ✗ python --version
Python 3.9.18
➜  dc-fabrics git:(main) ✗ pip freeze
attrs==23.2.0
colorama==0.4.6
deepmerge==1.1.1
importlib-metadata==4.13.0
Jinja2==3.1.4
jsonschema==4.22.0
jsonschema-specifications==2023.12.1
MarkupSafe==2.1.5
mypy-extensions==1.0.0
nornir==3.4.1
nornir-ansible==2023.12.28
nornir-utils==0.2.0
pyavd @ file:///home/carlbuchmann/git_projects/studios-builder-project/test-fabric/dc-fabrics/pyavd-4.8.0-py3-none-any.whl
referencing==0.35.1
rpds-py==0.18.1
ruamel.yaml==0.18.6
ruamel.yaml.clib==0.2.8
zipp==3.19.0