Fail when exporting all collections

[cuzureau]

When I run the program one collection at a time, it works.
But, when I run it with all collections exported trough Firebase and stored in GCP Storage in a folder under the name all_namespaces > all_kinds it fails.

I means the program run correctly, json files are created. But all json files are the same, all are equivalent to my first collection in Firebase.

[labbots]

I haven't tested it with multiple collections export. I will try and fix it when I get some time. In the meantime feel free to raise a PR if you manage to fix it first.