Update the list of contributors

Author: stephane-caron

CITATION.cff

@@ -29,3 +29,6 @@ authors:
   orcid: "https://orcid.org/0009-0003-4266-6652"
 - family-names: "Uruç"
   given-names: "Jafar"
+- family-names: "Traversaro"
+  given-names: "Silvio"
+  orcid: "https://orcid.org/0000-0002-9283-6133"

README.md

@@ -310,7 +310,7 @@ If you use this project in your works, please cite as follows:
 ```bibtex
 @software{robot_descriptions_py,
   title = {{robot_descriptions.py: Robot descriptions in Python}},
-  author = {Caron, Stéphane and Romualdi, Giulio and Kozlov, Lev and Ordoñez Apraez, Daniel Felipe and Tadashi Kussaba, Hugo and Bang, Seung Hyeon and Zakka, Kevin and Schramm, Fabian and Uru\c{c}, Jafar},
+  author = {Caron, Stéphane and Romualdi, Giulio and Kozlov, Lev and Ordoñez Apraez, Daniel Felipe and Tadashi Kussaba, Hugo and Bang, Seung Hyeon and Zakka, Kevin and Schramm, Fabian and Uru\c{c}, Jafar and Traversaro, Silvio},
   license = {Apache-2.0},
   url = {https://github.com/robot-descriptions/robot_descriptions.py},
   version = {1.15.0},