Update Joint limits for the joint head pan.

follow_joint_trajectory.md

@@ -298,7 +298,7 @@ You can also actuate a single joint for the Stretch. Below are the list of joint
 joint_lift:      lower_limit =  0.15,  upper_limit =  1.10  # in meters
 wrist_extension: lower_limit =  0.00,  upper_limit =  0.50  # in meters
 joint_wrist_yaw: lower_limit = -1.75,  upper_limit =  4.00  # in radians
-joint_head_pan:  lower_limit = -2.80,  upper_limit =  2.90  # in radians
+joint_head_pan:  lower_limit = -4.10,  upper_limit =  1.60  # in radians
 joint_head_tilt: lower_limit = -1.60,  upper_limit =  0.40  # in radians
 joint_gripper_finger_left:  lower_limit = -0.35,  upper_limit =  0.165  # in radians