Fixing dependency issue on Eagle installation

[nmerket]

Fixes #178.

Pull Request Description

A recent update to s3fs was causing dependency conflicts with boto3, so I pinned it to the older version that worked.

Installed in a new environment on Eagle and tested with a small batch run. Seems to work.

Checklist

Not all may apply

• Code changes (must work)
• Tests exercising your feature/bug fix (check coverage report on CircleCI build -> Artifacts)
• All other unit tests passing
• Update validation for project config yaml file changes
• Update existing documentation
• Run a small batch run to make sure it all works (local is fine, unless an Eagle specific feature)
• Add to the changelog_dev.rst file and propose migration text in the pull request

[asparke2]

Looks good, just successfully built and used an environment created with this code on Eagle.