building release packages outputs warnings with recent setuptools (?) version

[gdementen]

The warning below is repeated for:

• 'larray.tests.data'
• 'larray.tests.data.demography_eurostat'
• 'larray.tests.data.examples'
• 'larray.tests.data.excel_with_links'
• 'larray.tests.excel_template'

See https://dev.azure.com/conda-forge/feedstock-builds/_build/results?buildId=780525&view=logs&jobId=656edd35-690f-5c53-9ba3-09c10d0bea97&j=656edd35-690f-5c53-9ba3-09c10d0bea97&t=986b1512-c876-5f92-0d81-ba851554a0a3

          # Package would be ignored #
          ############################
          Python recognizes 'larray.tests.data' as an importable package[^1],
          but it is absent from setuptools' `packages` configuration.

          This leads to an ambiguous overall configuration. If you want to distribute this
          package, please make sure that 'larray.tests.data' is explicitly added
          to the `packages` configuration field.

          Alternatively, you can also rely on setuptools' discovery methods
          (for example by using `find_namespace_packages(...)`/`find_namespace:`
          instead of `find_packages(...)`/`find:`).

          You can read more about "package discovery" on setuptools documentation page:

          - https://setuptools.pypa.io/en/latest/userguide/package_discovery.html

          If you don't want 'larray.tests.data' to be distributed and are
          already explicitly excluding 'larray.tests.data' via
          `find_namespace_packages(...)/find_namespace` or `find_packages(...)/find`,
          you can try to use `exclude_package_data`, or `include-package-data=False` in
          combination with a more fine grained `package-data` configuration.

          You can read more about "package data files" on setuptools documentation page:

          - https://setuptools.pypa.io/en/latest/userguide/datafiles.html


          [^1]: For Python, any directory (with suitable naming) can be imported,
                even if it does not contain any `.py` files.
                On the other hand, currently there is no concept of package data
                directory, all directories are treated like packages.
          ********************************************************************************

[gdementen]

In setup.py, replacing find_packages by find_namespace_packages silences the warnings but I am not sure at this point whether it is the right thing to do.