[Examples] Add missing license

examples/python/kinematics-derivatives.py

+##
+## Copyright (c) 2018 CNRS
+##
+## This file is part of Pinocchio
+## Pinocchio is free software: you can redistribute it
+## and/or modify it under the terms of the GNU Lesser General Public
+## License as published by the Free Software Foundation, either version
+## 3 of the License, or (at your option) any later version.
+##
+## Pinocchio is distributed in the hope that it will be
+## useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+## of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+## General Lesser Public License for more details. You should have
+## received a copy of the GNU Lesser General Public License along with
+## Pinocchio If not, see
+## <http:##www.gnu.org/licenses/>.
+##
+
 import pinocchio as pin
 import numpy as np