Adds readthedocs yml file in order to specify python version for builds
This resolves the build failure that happened after merging the changes from !219 (merged)
JIRA tickets: SE-3944
Sandbox URL: https://handbook.opencraft.com/en/nizar-se-3944-fix-builds/
Merge deadline: ASAP
Testing instructions:
- Check the build#12853181 and verify that it succeeded.
- Check the sandbox url and make sure the cells page renders properly.
Reviewers
Edited by Nizar