Adding OSS Notification Classes for SMIGRATING and SMIGRATED. Handling of SMIGRATING is completed and covered with tests.#3849

petyaslavova merged 3 commits intofeat/hitless_upgrade_sync_cluster_clientredis/redis-py:feat/hitless_upgrade_sync_cluster_clientfrom

ps_add_cluster_related_notifications_and_handlersredis/redis-py:ps_add_cluster_related_notifications_and_handlersCopy head branch name to clipboard