Bump html5 so that jsdom becomes an optional dep.

Merged upstream in,
https://github.com/aredridel/html5/pull/93

Changes to the selser output are most likely due to,
https://github.com/aredridel/html5/pull/88

Change-Id: I5b409022c05c308b09d3b6d10ea45894a40e5edb