www/baikal: update to 0.7.1

• Configuration format was updated **

With the 0.7.0 release, our configuration format was updated to use YAML files.
You need to go through the installer again but we pre-fill most values with the
ones from your old installation. We recommend that you make a full backup of
your data, as a safety measure. Starting with 0.7.0, Baikal stores data in both
the Specific and the config folders. Keep this in mind when upgrading!

Known issue:: Upgrading from versions older than 0.6.1 does not work.

Release notes:
https://github.com/sabre-io/Baikal/releases/tag/0.7.0
https://github.com/sabre-io/Baikal/releases/tag/0.7.1