Update dependencies for security vulnerabilities

[bear]

pipfile.lock and requirements.txt need the following change applied:
django>=2.0.8

CVE-2018-14574
moderate severity
Vulnerable versions: >= 2.0, < 2.0.8
Patched version: 2.0.8
django.middleware.common.CommonMiddleware in Django 1.11.x before 1.11.15 and 2.0.x before 2.0.8 has an Open Redirect.

CVE-2018-6188
moderate severity
Vulnerable versions: >= 2.0.0, < 2.0.2
Patched version: 2.0.2
django.contrib.auth.forms.AuthenticationForm in Django 2.0 before 2.0.2, and 1.11.8 and 1.11.9, allows remote attackers to obtain potentially sensitive information by leveraging data exposure from the confirm_login_allowed() method, as demonstrated by discovering whether a user account is inactive.