Add a section about resigning

In the previous review, it was brought up that we should have a
responsibility for resigning should the event occur.  This commit
codifies that.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I491dda468a4f4368d7443ad84e9fffa9d9105f8d
diff --git a/community-membership.md b/community-membership.md
index 2d858ef..0bfcccb 100644
--- a/community-membership.md
+++ b/community-membership.md
@@ -128,6 +128,9 @@
   - Providing results and insight to the community on platform-specific issues.
 - Expected to be responsive to review requests as per [community expectations]
 - Assigned changes to review and test related to the platform
+- Communicating with the technical-oversight-forum any long-term (> 1 month)
+  absences, or resignation of these responsibilities, through a change to the
+  [OWNERS] file.
 
 ## Approver