amend merge criteria

the rule that the Oversight Committee needs to merge every dev-doc PR has not scaled with the project. We now write dev-docs for most design changes for any instructlab repo. This rule has also not regularly been followed.
Amend this rule such that and 2 maintainers of any instructlab repo can approve and merge, and an OC member can be brought in as well if needed.

Signed-off-by: Charlie Doern <cdoern@redhat.com>

Author: cdoern

README.md

@@ -24,7 +24,11 @@ please ping the Oversight Committee for help.
   out from maintainers of relevant components. The broader the scope or more
   controversial the change, the more broad the consensus should be required for
   merging. The final approval and merge (or action, e.g. deleting a repo)
-  falls to a member of the Oversight Committee. This final review is to ensure that
+  falls to two maintainers of any InstructLab Organization repository as well as
+  an additional third maintainer of any InstructLab Organization repository to
+  merge the PR, denoting that the sufficient reviews have been given. If there are
+  disputes on the design document that cannot be resolved, an Oversight Committee
+  member can be consulted as an arbitrator. These approvals ensure that
   adequate opportunity and attention has been given by the affected parties.
   * Examples of non-trivial changes include approving proposal for new repositories,
     creation of new repositories, changes to organization level GitHub settings, archiving