State bookmarks should use ids instead of repo names

[laurentS]

Following the same logic as what is described in #110 and the linked PR, the state bookmarks should use stable IDs for their context, as opposed to the current org / repo:
If a repo is renamed between 2 runs of the tap, the later run would ignore the bookmark, as the repo name would not match anymore. While not a disaster, it would essentially force a full resync of the history of the stream, which is a waste of time/energy/api quotas.

Example of a state bookmark right now:

    {
      "context": { "org": "scipy", "repo": "scipy" },  // this should use a stable id
      "replication_key": "updated_at",
      "replication_key_value": "2022-05-06T14:29:18Z",
      "replication_key_signpost": "2022-06-22T09:07:14.047100+00:00",
      "starting_replication_value": "2022-05-06T14:29:18Z",
      "progress_markers": {
        "Note": "Progress is not resumable if interrupted.",
        "replication_key": "updated_at",
        "replication_key_value": "2022-06-22T07:55:32Z"
      }
    },

[laurentS]

Relates to #122