Add DIRAC and diracx-api as dependencies

[Loxeris]

closes #46.

Add DIRAC and diracx-api as project dependencies.
These packages are currently required to resolve issues in ongoing development.

[aldbr]

Please could you just address the warning in the CI?

WARN Encountered 1 warning while parsing the manifest:
  ⚠ The `project` field is deprecated. Use `workspace` instead.
    ╭─[/home/runner/work/dirac-cwl-proto/dirac-cwl-proto/pyproject.toml:74:1]
 73 │     # -------------------------
 74 │ ╭─▶ [tool.pixi.project]
 75 │ │   channels = ["conda-forge"]
 76 │ ├─▶ platforms = ["linux-64", "osx-64", "osx-arm64"]
    · ╰──── replace this with 'workspace'
 77 │     
    ╰────

Other than that it looks good to me!