ModuleNotFoundError: No module named 'nowcasting_dataset.dataset.example' or 'pytorch_lightning'

[JackKelly]

Describe the bug
The unit tests on GitHub are currently failing:

Run pytest --cov=nowcasting_utils
============================= test session starts ==============================
platform linux -- Python 3.8.12, pytest-6.2.5, py-1.10.0, pluggy-1.0.0
rootdir: /home/runner/work/nowcasting_utils/nowcasting_utils
plugins: cov-3.0.0
collected 33 items / 2 errors / 31 selected

==================================== ERRORS ====================================
__________________ ERROR collecting tests/models/test_hub.py ___________________
ImportError while importing test module '/home/runner/work/nowcasting_utils/nowcasting_utils/tests/models/test_hub.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/importlib/__init__.py:127: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
tests/models/test_hub.py:6: in <module>
    from nowcasting_utils.models.base import BaseModel
nowcasting_utils/models/base.py:10: in <module>
    import pytorch_lightning as pl
E   ModuleNotFoundError: No module named 'pytorch_lightning'
__________ ERROR collecting tests/visualization/test_visualization.py __________
ImportError while importing test module '/home/runner/work/nowcasting_utils/nowcasting_utils/tests/visualization/test_visualization.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/importlib/__init__.py:127: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
tests/visualization/test_visualization.py:1: in <module>
    from nowcasting_utils.visualization.visualization import plot_example
nowcasting_utils/visualization/visualization.py:13: in <module>
    from nowcasting_dataset.dataset.example import DATETIME_FEATURE_NAMES
E   ModuleNotFoundError: No module named 'nowcasting_dataset.dataset.example'

Additional context

https://github.com/openclimatefix/nowcasting_utils/runs/3930110477?check_suite_focus=true