I don't know the exact date.
https://ballotpedia.org/RNC_Rules_Committee,_2016
The committee formally begins its deliberations the week before the convention begins. On the first day of the convention, it proposes a rules package to the convention’s delegates, who, in turn, are responsible for approving the proposed rules by a majority vote or sending them back to the Rules Committee.[2]
Thanks, seems like the meeting would have to be some time this week. Maybe there will be some mention of it in the news when it begins.