There have been some new dependencies added in recent versions of
Twisted (mostly internal classes that have been spun out into their own
libraries):

* constantly (#5453), since 16.5.0
* incremental (#5454), since 16.5.0
* Automat (#5456), since 17.1.0
* hyperlink (#5455) since 17.5.0

Signed-off-by: Jeffery To <jeffery.to@gmail.com>