Fixes bug introduced in issue/34
Due to a bug all public bucket urls were generated using the internal client. Due to this fault public urls did not respect the value of `MINIO_EXTERNAL_ENDPOINT`.
The old fake client was repurposed as an external client.
Additional changes:
* Dropped the `v` prefix from version numbers
* GH workflows updated to the latest Ubuntu and Python versions and updated the watched tags
* [README.md](README.md) updated with new Python version recommendations