Bump Python 3 packages version for FreeBSD

Summary:
Most packages are now built for Python 3.7 in binary packages.

Fixes T1570.

Test Plan: salt windriver state.sls_id install_salt_extra_software roles/saltmaster

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T1570

Differential Revision: https://devcentral.nasqueron.org/D2150