Update Ranking metrics notebook example to pin whylogs version install (#1483)

## Description

The ranking metrics example notebook has a bug when used with latest
whylogs version, while those bugs are being addressed let's pin the
install to the version this notebook example was based on to mitigate.

## Changes

- specify version 1.3.21 when installing whylogs in the notebook
example.

## Related

Avoids the error but does not address underlying root cause of #1480 


- [x] I have reviewed the [Guidelines for Contributing](CONTRIBUTING.md)
and the [Code of Conduct](CODE_OF_CONDUCT.md).

Author: jamie256