Update requirements.txt
Update requirements.txt

Fixes:
 - https://github.com/sholsapp/cthulhu/network/alert/requirements.txt/Jinja2/open
 - https://github.com/sholsapp/cthulhu/network/alert/requirements.txt/urllib3/open
 - https://github.com/sholsapp/cthulhu/network/alert/requirements.txt/requests/open
corelabsio/cthulhu,corelabsio/cthulhu