Update html5 package from upstream.

Up to date with HEAD aredridel/html5/a0fde78d9b8a00a03f09bade00c215db51545842,
which is slightly ahead of v0.3.14.

Previous version seems to be around v0.3.8,
closer to commit aredridel/html5/b43562a48f63ae72a91694dd77ac5b8d97d624e0.

Adds a dependency on html5-entities.

Bug: 47323
Change-Id: Id3f39d4725a4d4c342368fa2e2047ad454e1e8b5
Merge "Update html5 package from upstream."