Update CSS video-dynamic-range spec URL (#16754)
Update CSS video-dynamic-range spec URL (#16754)

As with #16746, this should be using the drafts.csswg.org spec URL
rather than a www.w3.org/TR URL.
chrisdavidmills/browser-compat-data,mdn/browser-compat-data,mdn/browser-compat-data,chrisdavidmills/browser-compat-data