[fix] missing const in arguments of RobotWrapper.set_rotor_inertia and RobotWrapper.set_gear_ratios python bindings

[domrachev03]

This MR adds missing const identifier to the arguments of two methods of RobotWrapper: set_rotor_inertia and set_gear_ratios in python bingings. This problem practically disallowed to use motor inertia in python bindings.

Right now, this functionality does not work, and an attempt to run the simplest example:

from copy import deepcopy

import numpy as np
import pinocchio as pin
import tsid
from robot_descriptions.iiwa7_description import URDF_PATH

pin_model = pin.buildModelFromUrdf(URDF_PATH)
robot = tsid.RobotWrapper(pin_model, False)

robot.set_gear_ratios(np.ones(12))
robot.set_rotor_inertias(np.ones(12))

print(robot.rotor_inertias)
print(robot.gear_ratios)

results in:

Boost.Python.ArgumentError: Python argument types in
    RobotWrapper.set_gear_ratios(RobotWrapper, numpy.ndarray)
did not match C++ signature:
    set_gear_ratios(tsid::robots::RobotWrapper {lvalue}, Eigen::Matrix<double, -1, 1, 0, -1, 1> {lvalue} gear ratio vector)

[nim65s]

Thanks !
Could you add a regression test, to avoid this issue to happen again ?

[domrachev03]

Done! I've modified a tests/python/test_RobotWrapper test to add a motor's inertias and check that it's computed correctly.

I am not 100% sure I correctly understood what do you mean by regression test, and if you want me to implement smth else, I would be glad to do that!

[nim65s]

You did exactly what was expected, thanks !

[domrachev03]

Glad to hear that! Since the pipeline is failing in the devel as well, I guess we are good to merge those changes? Or something else is missing?

[nim65s]

Yes, both Gitlab & ROS CI are fine, so we can merge :)