while trying to build the backend:

`INFO: pip is looking at multiple versions of celery to determine which version is compatible with other requirements. This could take a while.
INFO: pip is looking at multiple versions of bcrypt to determine which version is compatible with other requirements. This could take a while.
INFO: pip is looking at multiple versions of authlib to determine which version is compatible with other requirements. This could take a while.
INFO: pip is looking at multiple versions of alembic to determine which version is compatible with other requirements. This could take a while.
ERROR: Cannot install -r requirements.txt (line 3) and starlette==0.13.8 because these package versions have conflicting dependencies.

The conflict is caused by:
The user requested starlette==0.13.8
fastapi 0.61.1 depends on starlette==0.13.6

To fix this you could try to:

1. loosen the range of package versions you've specified
2. remove package versions to allow pip attempt to solve the dependency conflict

ERROR: ResolutionImpossible: for help visit https://pip.pypa.io/en/latest/user_guide/#fixing-conflicting-dependencies
ERROR: Service 'backend' failed to build : The command '/bin/sh -c pip install --no-cache-dir -r requirements.txt' returned a non-zero code: 1