found some more URLs to update

CONTRIBUTING.md

 # CONTRIBUTING TO THE COQ-STD++ DEVELOPMENT
 
 If you want to report a bug, please use the
-[issue tracker](https://gitlab.mpi-sws.org/robbertkrebbers/coq-stdpp/issues).
-You will have to create an account at the
+[issue tracker](https://gitlab.mpi-sws.org/iris/stdpp/issues).  You will have to
+create an account at the
 [MPI-SWS GitLab](https://gitlab.mpi-sws.org/users/sign_in) (use the "Register"
 tab).
 
 To contribute code, please send your MPI-SWS GitLab username to
 [Ralf Jung](https://gitlab.mpi-sws.org/jung) to enable personal projects for
 your account.  Then you can fork the
-[Coq-std++ git repository](https://gitlab.mpi-sws.org/robbertkrebbers/coq-stdpp),
-make your changes in your fork, and create a merge request.
+[Coq-std++ git repository](https://gitlab.mpi-sws.org/iris/stdpp), make your
+changes in your fork, and create a merge request.