security/py-social-auth-core: Update to 4.8.1

• Fold PING option as py-python-json was replaced with py-pyjwt, which is a basic dependency, for the Ping Identity backend.

Changelog since 4.7.1:

https://github.com/python-social-auth/social-core/blob/4.8.1/CHANGELOG.md

PR: 290527
Approved by: maintainer timeout (14+ days)