Update package format to pyproject.toml

[DanielRubianes]

I encountered this problem when attempting to install the module in my pyhton 3.13 environment:

> pip install -e .
Obtaining <path>/directus-sdk-python
  ...
  × Getting requirements to build editable did not run successfully.
  │ exit code: 1
  ╰─> [30 lines of output]
          ...
          from directus.clients import DirectusClient_V9
        File "<path>\directus-sdk-python\directus\clients.py", line 1, in <module>
          import requests
      ModuleNotFoundError: No module named 'requests'
      [end of output]

  note: This error originates from a subprocess, and is likely not a problem with pip.
error: subprocess-exited-with-error

× Getting requirements to build editable did not run successfully.
│ exit code: 1
╰─> See above for output.

note: This error originates from a subprocess, and is likely not a problem with pip.

Switching to pyproject.toml seemed to resolve the issue, I would guess due to better handling of dependencies, with explicitly defined versions. Let me know if there is a better solution; among the mess of Directus Python SDK repos, this one has the most functionality we need.