Adjust options to prometheus 1.6

Change-Id: I366b9fbef37bde5110515e0f8ac13110d5ab4b8b
diff --git a/metadata/service/server/container.yml b/metadata/service/server/container.yml
index 38facc3..050fb8c 100644
--- a/metadata/service/server/container.yml
+++ b/metadata/service/server/container.yml
@@ -16,8 +16,7 @@
         local:
           engine: "persisted"
           retention: "360h"
-          memory_chunks: 1048576
-          max_chunks_to_persist: 524288
+          target_heap_size: 3221225472
           num_fingerprint_mutexes: 4096
       alertmanager:
         notification_queue_capacity: 10000