Setuptools: data is deprecated, please list it in `packages`

Am seeing the following warning in builds of `distributed`. This is coming from Setuptools.

```python
/home/conda/feedstock_root/build_artifacts/distributed_1660950755740/_h_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold/lib/python3.10/site-packages/setuptools/command/build_py.py:202: SetuptoolsDeprecationWarning: Installing 'distributed.dashboard.templates' as data is deprecated, please list it in `packages`.
!!

############################
# Package would be ignored #
############################
Python recognizes 'distributed.dashboard.templates' as an importable package,
but it is not listed in the `packages` configuration of setuptools.

'distributed.dashboard.templates' has been automatically added to the distribution only
because it may contain data files, but this behavior is likely to change
in future versions of setuptools (and therefore is considered deprecated).

Please make sure that 'distributed.dashboard.templates' is included as a package by using
the `packages` configuration field or the proper discovery methods
(for example by using `find_namespace_packages(...)`/`find_namespace:`
instead of `find_packages(...)`/`find:`).

You can read more about "package discovery" and "data files" on setuptools
documentation page.

```

Have [attached a full build log]( https://github.com/dask/distributed/files/9385771/distributed-feedstock-20220819.5_linux-64.txt ) for more details.

IIUC this traces back to this

https://github.com/dask/distributed/blob/a80187a23bd317136d5dbbb02068bc8f90055e4e/setup.py#L39-L43

cc @jrbourbeau