[README.md] Remove link to travis and change it to BSD clause 2 license.

Author: olivier-stasse

README.md

@@ -2,7 +2,7 @@ sot-dynamic-pinocchio
 Encapsulate Pinocchio in SoT
 ===========
 
-[![Building Status](https://travis-ci.org/stack-of-tasks/sot-dynamic-pinocchio.svg?branch=master)](https://travis-ci.org/stack-of-tasks/sot-dynamic-pinocchio)
+[![License](https://img.shields.io/badge/License-BSD%202--Clause-green.svg)](https://opensource.org/licenses/BSD-2-Clause)
 [![Pipeline status](https://gitlab.laas.fr/stack-of-tasks/sot-dynamic-pinocchio/badges/master/pipeline.svg)](https://gitlab.laas.fr/stack-of-tasks/sot-dynamic-pinocchio/commits/master)
 [![Coverage report](https://gitlab.laas.fr/stack-of-tasks/sot-dynamic-pinocchio/badges/master/coverage.svg?job=doc-coverage)](http://projects.laas.fr/gepetto/doc/stack-of-tasks/sot-dynamic-pinocchio/master/coverage/)