v1.3.0

This release primarily focuses on improving the Robot class:

• Only parse the non-fixed joints of the robot by default.
• Allow manually specifying which joints are actuated.
• Add the set_joint_friction_force method to enable free-moving joints.
• Add the command_effort method for torque joint.
• Add the as_rotation_matrix argument to the get_link_pose methods to automatically convert the quaternion to a rotation matrix before returning it.

Two new examples have also been added: an under-actuated 2-link planar pendulum and a task-space robot arm control demo.

Finally, the function get_urdf_path has also been added to obtain URDFs packaged with pyb_utils (currently only the two-link pendulum mentioned above).