update url models on example.sh

[CristobalRR]

the name of the models used for the example has changed and need to be updated
- old url: http://data.statmt.org/bergamot/models/deen/ende.student.tiny11.tar.gz
- new url: https://data.statmt.org/bergamot/models/deen/ende.student.tiny11.v2.93821e13b3c511b5.tar.gz