[Reverb] Update citation.
[Reverb] Update citation.

Commas are used for last name/first name, and is used to distinguish authors.

PiperOrigin-RevId: 377933374
Change-Id: I5a959916dfa63afebb5542bab56ede9734dbc622

deepmind/reverb,deepmind/reverb,deepmind/reverb,deepmind/reverb