iproto: add new protocol feature codes

IPROTO_FEATURE_PAGINATION (code 4) and protocol version 4 was added in
Tarantool master [1].

1. tarantool/tarantool@948e5cd

Part of #267

Author: DifferentialOrange

Diff for: tarantool/const.py

@@ -96,6 +96,7 @@
 IPROTO_FEATURE_TRANSACTIONS = 1
 IPROTO_FEATURE_ERROR_EXTENSION = 2
 IPROTO_FEATURE_WATCHERS = 3
+IPROTO_FEATURE_PAGINATION = 4
 
 # Default value for connection timeout (seconds)
 CONNECTION_TIMEOUT = None
@@ -126,7 +127,7 @@
 # Default delay between attempts to reconnect (seconds)
 POOL_INSTANCE_RECONNECT_DELAY = 0
 
-# Tarantool 2.10 protocol version is 3
-CONNECTOR_IPROTO_VERSION = 3
+# Tarantool master 948e5cdc (possible 2.11) protocol version is 4
+CONNECTOR_IPROTO_VERSION = 4
 # List of connector-supported features
 CONNECTOR_FEATURES = [IPROTO_FEATURE_ERROR_EXTENSION,]