In Tutor core & plugins, the minimum Python version should be bumped from 3.8 to 3.9

[regisb]

Is your feature request related to a problem? Please describe.

Python 3.8 is reaching end-of-life on Oct. 31st: https://endoflife.date/python This means that the minimum supported version of Tutor should bump to 3.9.

Describe the solution you'd like

1. we should bump the minimum required version of Tutor and all plugins to 3.9.
2. CI must be upgraded to build binaries with 3.9.
3. We must get rid of documentation warnings triggered by python 3.8
4. Basically, all references to 3.8 must be removed.

[DawoudSheraz]

PRs for Tutor core and plugins (some plugins might be removed from list if the action is not needed)

• Tutor chore: remove Python 3.8 references #1150
• tutor-indigo chore: remove python 3.8 references tutor-indigo#103
• tutor-mfe chore: remove python 3.8 references tutor-mfe#236
• tutor-ecommerce chore: remove Python 3.8 references tutor-ecommerce#86
• tutor-discovery chore: remove Python 3.8 references tutor-discovery#91
• tutor-credentials chore: remove Python 3.8 references tutor-credentials#51
• tutor-minio chore: remove Python 3.8 references tutor-minio#54
• tutor-forum chore: remove python 3.8 references and set py39 as minimum version tutor-forum#53
• tutor-notes chore: remove python 3.8 references and set py39 as minimum version tutor-notes#42
• tutor-xqueue chore: remove python 3.8 references and set py39 as minimum version tutor-xqueue#35
• tutor-jupyter chore: remove python 3.8 references tutor-jupyter#16
• tutor-webui chore: remove python 3.8 references tutor-webui#21
• tutor-android chore: remove python 3.8 references tutor-android#32
• tutor-cairn chore: remove python 3.8 references tutor-cairn#48
• cookiecutter-tutor-plugin chore: remove Python 3.8 references cookiecutter-tutor-plugin#37

[regisb]

Let me know once you are ready and I can either open PRs or push straight to the repos.

[DawoudSheraz]

All PRs have been merged, closing this issue.