Be more strict on PSA requirements

0.1.24 - 0.1.26 suffer by
https://github.com/omab/python-social-auth/issues/291

Consequent releases will change API for pipeline and the new API is not
supported by Weblate (and I'm not sure if it will be possible to support
both of them).

Signed-off-by: Michal Čihař <michal@cihar.com>