API version for OpenCitations #102
Description
For OpenCitations, we currently the v1 COCI API:
https://opencitations.net/index/coci/api/v1
This seems to be out of date, with there now being a newer v2 API:
https://opencitations.net/index/api/v2
In the new API, some of the operations have changed a bit, and there would need to be a bit of updating on this.
As it currently stands, the v1 API seems like it should still be supported / work - but at the moment the tests are failing and the API doesn't seem to be returning properly. Regardless of whether this is a long term change, it's probably worth updating to use the v2 API anyways.