fix(github-integration): __str__ for GitHub_Issue model (#4282)
fix(github-integration): __str__ for GitHub_Issue model (#4282)

the str was referencing invalid field names, causing an exception when trying to delete a product with github integration enabled.
rackerlabs/django-DefectDojo,rackerlabs/django-DefectDojo,rackerlabs/django-DefectDojo,rackerlabs/django-DefectDojo