The latest revision of the CRB has a nylon or delrin plastic inner race and no grease is desired. If you have the new version, the answer is "none". The delrin is prepreg with teflon and grease will only trap clutch dust and increase wear.
If you have the older style, most any lithium grease will meet or exceed the requirements of the Esso Unirex S-2 specified in TIS. The bearing itself is pre-greased, but TIS specifies contact points between the release fork to CRB and release fork to ball pivot and slave piston face be greased as well.
Most CRBs that come out will show some wear/galling on the metal CRB flat (keyed) sides to the release fork.
The redesigned CRB has two raised dimples on the keyed flats to align the flats and prevent galling due to rotational misalignment, again in delrin, so no grease recommended.
Should be fine, but go very light. The more you use, the more dust will be attracted to it.