Inconsistent entry.time across browsers

[satyamk7054]

Spaniel's polyfill for IntersectionObserver uses Date.now() for setting entry.time, which is relative to epoch. The native implementation defines entry.time as being relative to the creation of the document (ref: https://developer.mozilla.org/en-US/docs/Web/API/IntersectionObserverEntry/time).

[lynchbomb]

@satyamk7054 thank you for raising this to our attention. @asakusuma and I have chatted concerning and the current plan is to implement this fix forward within a new spaniel release (v5.x.x) as this will be a breaking change.

If you have cycles to work on this, a PR would be more than welcome :) Otherwise we will queue the work.