Bump kombu from 4.5.0 to 4.6.0 in /backend/uclapi
Bump kombu from 4.5.0 to 4.6.0 in /backend/uclapi

Bumps [kombu](https://kombu.readthedocs.io) from 4.5.0 to 4.6.0.
uclapi/uclapi,uclapi/uclapi,uclapi/uclapi,uclapi/uclapi