share: show warning if share is outdated while source supports share-safe Previous patches in the series and some which are already committed implements share safe functionality where config and requirements will be shared too. Rolling this feature has a problem that existing shares may never upgrade as they will never learn about the new config. To help the transition, we show a warning message if the share source supports share-safe mechanism. This provides the source repo ability to upgrade and pass on the message to shares that you should reshare and upgrade too. Differential Revision: https://phab.mercurial-scm.org/D9369