Bump auth-backends to 0.5.1
Bump auth-backends to 0.5.1

Requires at least PSA 0.2.20, which includes an index on the Association model.

eduNEXT/edunext-ecommerce,eduNEXT/edunext-ecommerce,edx/ecommerce,edx/ecommerce,mferenca/HMS-ecommerce,eduNEXT/edunext-ecommerce,eduNEXT/edunext-ecommerce,mferenca/HMS-ecommerce,edx/ecommerce,edx/ecommerce,mferenca/HMS-ecommerce