Upgrade python-dateutil dependency to a newer version

Is your feature request related to a problem? Please describe.

I came up with a dependency problem using scoutsuite and some other tools that rely on newer versions of python-dateutil. The incompatibility makes it impossible for me to use both tools in one project.

Describe the solution you'd like

I didn't test it locally but I'd suggest to just use a newer version of python-dateutil. I wonder if there were problems with it because the version is pinned currently between 2.1 and 2.8.1.