Figure out what's causing a bug in the CI pipeline

[matthewcarbone]

_______________ ERROR collecting tests/test_models/test_mpnn.py ________________
ImportError while importing test module '/home/runner/work/crescendo/crescendo/tests/test_models/test_mpnn.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/usr/share/miniconda/lib/python3.7/importlib/__init__.py:127: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
tests/test_models/test_mpnn.py:3: in <module>
    from crescendo.models.mpnn import MPNN
crescendo/models/mpnn.py:5: in <module>
    from dgllife.model import MPNNPredictor
/usr/share/miniconda/lib/python3.7/site-packages/dgllife/__init__.py:9: in <module>
    from . import model
/usr/share/miniconda/lib/python3.7/site-packages/dgllife/model/__init__.py:8: in <module>
    from .model_zoo import *
/usr/share/miniconda/lib/python3.7/site-packages/dgllife/model/model_zoo/__init__.py:33: in <module>
    from .acnn import *
/usr/share/miniconda/lib/python3.7/site-packages/dgllife/model/model_zoo/acnn.py:14: in <module>
    from dgl import BatchedDGLHeteroGraph
E   ImportError: cannot import name 'BatchedDGLHeteroGraph' from 'dgl' (/usr/share/miniconda/lib/python3.7/site-packages/dgl/__init__.py)

[matthewcarbone]

Documented issue on dgllife:

https://github.com/awslabs/dgl-lifesci/issues/70

Fun stuff.

[matthewcarbone]

For now, use a previous version of dgllife until they fix it!

[matthewcarbone]

Current working version of dgllife is 0.2.2.