Packages missing from built bundle

I am building the circuitpython community bundle, and followed the directions in the README:

```
git submodule init
git submodule update
./update-submodules.sh
circuitpython-build-bundles --filename_prefix adafruit-circuitpython-bundle --library_location libraries --library_depth 2
```

the bundle builds without error.

I'm interested in drivers that are packages, for example ``wiichuck``, but none of them are present in my bundle:

```
$ unzip -l bundles/adafruit-circuitpython-bundle-py-20210209.zip|grep wiichuck
497 2021-02-09 19:18 adafruit-circuitpython-bundle-py-20210209/examples/wiichuck_simpletest.py
```

Whereas when I look in the public release bundle, ``wiichuck`` is present:

```
$ unzip -l circuitpython-community-bundle-py-20210209.zip | grep wiichuck
4495 2021-02-09 05:09 circuitpython-community-bundle-py-20210209/lib/wiichuck/guitar.py
3288 2021-02-09 05:09 circuitpython-community-bundle-py-20210209/lib/wiichuck/udraw.py
2518 2021-02-09 05:09 circuitpython-community-bundle-py-20210209/lib/wiichuck/__init__.py
4987 2021-02-09 05:09 circuitpython-community-bundle-py-20210209/lib/wiichuck/classic_controller.py
5001 2021-02-09 05:09 circuitpython-community-bundle-py-20210209/lib/wiichuck/dj_table.py
3465 2021-02-09 05:09 circuitpython-community-bundle-py-20210209/lib/wiichuck/nunchuk.py
497 2021-02-09 05:09 circuitpython-community-bundle-py-20210209/examples/wiichuck_simpletest.py
```

I checked that ``libraries/drivers/wiichuck/`` exists in my tree and is populated. It is strange the the wiichuck **example** does get built, but the **driver** does not.

The same is true of every submodule that builds a package. The .zip I build contains no subdirectories under lib/, only .py files.

Building on Python 3.8, with tools version 1.6.0 in a venv as recommended, on both Ubuntu 18.04 and 20.04.

Start with the bundle-building directions in README and reproduce the issue using update-submodules.sh and circuitpython-build-bundles with libraries as the library location. Inspect how the builder handles libraries/drivers/wiichuck and package directories, then compare the generated zip with the public bundle. Done means package subdirectories such as lib/wiichuck are included, not only the example file.

Written by the indexing model from the issue text.