Version is not specified in pyproject.toml

[fxcoudert]

Build with recent maturin versions fail with (conda-forge/libipld-feedstock#3):

  💥 maturin failed
    Caused by: `project.version` field is required in pyproject.toml unless it is present in the `project.dynamic` list
  Error running maturin: Command '['maturin', 'pep517', 'write-dist-info', '--metadata-directory', '/private/tmp/pip-modern-metadata-3b7_jndi', '--interpreter', '/Users/runner/miniforge3/conda-bld/libipld_1735296838707/_h_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_p/bin/python']' returned non-zero exit status 1.
  error: subprocess-exited-with-error
  
  × Preparing metadata (pyproject.toml) did not run successfully.
  │ exit code: 1
  ╰─> See above for output.

This is due to maturin 1.8.0 which contains PyO3/maturin#2391
The version should be specified explicitly.