Fix code packaging when the flow file is in the root directory

[savingoyal]

From Darshan Patel on Metaflow Slack -

hey team, I'm getting an error while running a flow on AWS Batch. Metaflow is able to create a batch job definition and kicks a run on Batch but on the batch agent I'm getting following error. do you know what can cause this error?

Setting up task environment.
Downloading code package...
Code package downloaded.
Task is starting.
python: can't open file 'test.py': [Errno 2] No such file or directory