Implement safety check to check if our dependencies are somewhat up-to-date

dev-requirements.txt

@@ -6,3 +6,4 @@ pydenticon>=0.3.1
 pylint
 pylint-django
 tox
+safety

tox.ini

@@ -17,6 +17,7 @@ commands =
     python manage.py templatecheck --project-only
     python manage.py makemigrations --no-input --check --dry-run
     python -Wall -mcoverage run --branch --source '.' manage.py test
+    safety check
 deps = 
     coverage
     pip-conflict-checker