Overall Plan.rst was moved away; Update link to milestones since we made them...

Overall Plan.rst was moved away; Update link to milestones since we made them group milestones a while ago.

README.md

@@ -9,7 +9,7 @@ Its first user-facing milestone is to provide a read-only view of data managed f
 
 ## Overall plan
 
-See [this document on the next steps](Overall Plan.rst) until we have [milestones](https://whetstone.private.storage/privatestorage/privatestoragemobile/-/milestones) and [tickets](https://whetstone.private.storage/privatestorage/privatestoragemobile/-/issues) and better visibility on who's working on what, what's completed, and what's blocking.
+We have [milestones](https://whetstone.private.storage/groups/privatestorage/-/milestones?search_title=Mobile%3A&sort=start_date_desc&state=all) and [tickets](https://whetstone.private.storage/privatestorage/privatestoragemobile/-/issues) for a rough idea of who's working on what, what's completed, and what's blocking.
 
 ## Project status