A look at the traceback shows this problem
ContextualVersionConflict: (python-dateutil 2.7.2 (/home/frappe/frappe-bench/env/lib/python2.7/site-packages), Requirement.parse(‘python-dateutil<2.7.0,>=2.1’), set([‘botocore’]))
And a search shows these too related to it:
How to fix this botocore requirement?
Error Messages while running bench update