Fix logical replication protocol comparison logic

Since we currently only have one protocol, this doesn't make much of a
difference other than the error message.

Author: Yugo Nagata <nagata@sraoss.co.jp>

src/backend/replication/pgoutput/pgoutput.c

@@ -173,7 +173,7 @@ pgoutput_startup(LogicalDecodingContext *ctx, OutputPluginOptions *opt,
 								&data->publication_names);
 
 		/* Check if we support requested protocol */
-		if (data->protocol_version != LOGICALREP_PROTO_VERSION_NUM)
+		if (data->protocol_version > LOGICALREP_PROTO_VERSION_NUM)
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("client sent proto_version=%d but we only support protocol %d or lower",