Fix AWS download errors

[jashapiro]

Fixes problems with AWS downloads: tested the changes and they seem to work.

From @davidmejia's earlier PR:

Apparently github and aws are having trouble communicating and setting the env var AWS_EC2_METADATA_DISABLED to true will remedy this.

Context:

• https://github.com/aws/aws-cli/issues/5623
• https://notestoself.dev/posts/github-action-s3-botocore-awsrequest-process-255-error/