automate conf.py version info

[devyte]

Basic Infos

• This issue complies with the issue POLICY doc.
• I have read the documentation at readthedocs and the issue is not addressed there.
• I have tested that the issue is present in current master branch (aka latest git).
• I have searched the issue tracker for a similar issue.
• I have filled out all fields below.

Platform

• Document build system

Problem Description

Per @igrr 's comment here, conf.py can have its version info automated. This would remove one manual step in the release procedure.