Update API Verify list

Author: Arkatufus

src/core/Akka.API.Tests/CoreAPISpec.ApprovePersistenceSqlCommon.verified.txt

@@ -221,7 +221,8 @@ namespace Akka.Persistence.Sql.Common.Journal
         public readonly System.TimeSpan Timeout;
         public readonly string TimestampColumnName;
         public QueryConfiguration(string schemaName, string journalEventsTableName, string metaTableName, string persistenceIdColumnName, string sequenceNrColumnName, string payloadColumnName, string manifestColumnName, string timestampColumnName, string isDeletedColumnName, string tagsColumnName, string orderingColumnName, string serializerIdColumnName, System.TimeSpan timeout, string defaultSerializer, bool useSequentialAccess) { }
-        [System.ObsoleteAttribute("This property will always return null")]
+        [System.ObsoleteAttribute("This property should never be used, use the default `System.Object` serializer in" +
+            "stead")]
         public string DefaultSerializer { get; }
         public string FullJournalTableName { get; }
         public string FullMetaTableName { get; }