Correct 3rd-party-packages link in issue template.

Closes #6457

Author: carltongibson

ISSUE_TEMPLATE.md

@@ -3,7 +3,7 @@
 - [ ] I have verified that that issue exists against the `master` branch of Django REST framework.
 - [ ] I have searched for similar issues in both open and closed tickets and cannot find a duplicate.
 - [ ] This is not a usage question. (Those should be directed to the [discussion group](https://groups.google.com/forum/#!forum/django-rest-framework) instead.)
-- [ ] This cannot be dealt with as a third party library. (We prefer new functionality to be [in the form of third party libraries](https://www.django-rest-framework.org/topics/third-party-resources/#about-third-party-packages) where possible.)
+- [ ] This cannot be dealt with as a third party library. (We prefer new functionality to be [in the form of third party libraries](https://www.django-rest-framework.org/community/third-party-packages/#about-third-party-packages) where possible.)
 - [ ] I have reduced the issue to the simplest possible case.
 - [ ] I have included a failing test as a pull request. (If you are unable to do so we can still accept the issue.)