Import error when launching run script

Describe the bug Run is scheduled in Experiment in azure ML, docker builds image correctly, but when executing train.py script we get the following error:

  File "train.py", line 15, in <module>
    from arcus.ml.images import *
  File "/azureml-envs/azureml_c8679ff754035121fa7879f8b571ce9a/lib/python3.6/site-packages/arcus/ml/images/io.py", line 8, in <module>
    from cv2 import imread, imdecode, IMREAD_COLOR
  File "/azureml-envs/azureml_c8679ff754035121fa7879f8b571ce9a/lib/python3.6/site-packages/cv2/__init__.py", line 5, in <module>
    from .cv2 import *
ImportError: libGL.so.1: cannot open shared object file: No such file or directory

Seems as though a lib is to be added to the build.

To Reproduce Run a default arcus training script with any train.py script

from arcus.azureml.environment.aml_environment import AzureMLEnvironment

work_env = AzureMLEnvironment.Create(config_file="../.azureml/config.json")

training_name = 'your_training_name'
trainer = work_env.start_experiment(training_name)
trainer.setup_training(training_name, overwrite=False)

dataset_name = 'your_dataset_name'

arguments = {
    '--epochs': 75,
    '--batch_size': 256,
    '--es_patience': 20,
    '--train_test_split_ratio': 0.08
}
trainer.start_training(training_name, estimator_type='tensorflow', 
                       input_datasets = [dataset_name], 
                       compute_target='your_instance', gpu_compute=True, script_parameters = arguments)

Expected behavior Should launch training as if it were on local, but in the cloud within a run in an experiment.

arcus-azure / arcus.azureml

Import error when launching run script #95