Change CI to GitHub actions

Use copier template from oca/oca-addons-repo-template

Target Python3.8

Apply linting

Fix a missing call to super
Ensure all modules have a 13.0.x.x.x version

session_redis/json_encoding.py

@@ -2,7 +2,6 @@
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html)
 
 import json
-
 from datetime import date, datetime
 
 import dateutil