Adding E4 to the list of correct options (#158)

* Adding E4 to the list of correct options

* Update process_hand_type_version_side_parameters.xacro

sr_description/hand/xacro/process_hand_type_version_side_parameters.xacro

@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <!--
  Software License Agreement (BSD License)
- Copyright © 2022 belongs to Shadow Robot Company Ltd.
+ Copyright © 2022-2023 belongs to Shadow Robot Company Ltd.
  All rights reserved.
  Redistribution and use in source and binary forms, with or without modification,
  are permitted provided that the following conditions are met:
@@ -27,7 +27,7 @@
 <robot xmlns:xacro="http://www.ros.org/wiki/xacro">
 	<xacro:include filename="$(find sr_description)/hand/xacro/validate_macros.xacro" />
 	<xacro:property name="allowed_hand_types" value="${python.set('hand_e hand_g hand_c'.split())}" />
-	<xacro:property name="allowed_hand_versions" value="${python.set('E3M5 E2M3 C6M2 G1M5'.split())}"/>
+	<xacro:property name="allowed_hand_versions" value="${python.set('E4 E3M5 E2M3 C6M2 G1M5'.split())}"/>
         <xacro:property name="allowed_sides" value="${python.set('right left'.split())}"/>
         <xacro:property name="allowed_mounting_plate" value="${python.set([False, True])}"/>