GitHub blog recently announced a couple of interesting new features.
Firstly, Security Alerts. For now it only supports Ruby and JavaScript, but hopefully other languages are coming soon (PHP/Composer please!). Security Alerts will notify repository owners if there are any known security issues in any of the packages that the repository is using. Similar, I guess, to who SensioLabs Security Check works, but integrated with your GitHub.
Secondly, Team Discussions. This is yet another way place for the team to communicate. There are Issues and Pull Requests already. But those are more specific and more focused. For anything that doesn’t have a single issue, or doesn’t have a PR yet, a Team Discussion might be a better place.