You have to be proactive, but the specifics will vary depending on how you do your hiring. That may look like specifically requesting that employees belonging to underrepresented groups volunteer for recruitment, or best-effort selecting each candidate's panel to represent as many groups as possible. You could do quotas for the panelists, but only if participation wasn't important for career progress. To be clear: these quotas would only apply to members of the panel selected from the pool of eligible employees. Hiring quotas are unfair and harmful.