fix datetime-local timezone offset

[mbostock]

Ref. https://talk.observablehq.com/t/input-datetime-fails-the-identity-test/7222/3

[mootari]

Looks like we're already passing the wrong date to the input. From what I understand datetime-local will interpret the date in the local timezone, but we pass a UTC date string, resulting in a wrong time offset.

[mbostock]

Is that screenshot testing this PR? Or the released version on Observable?

[mbostock]

What I see in this PR is the intended behavior…

[mootari]

Sorry, I didn't understand that the PR also takes care of that. Confirmed with a local build that it's fixing the issue.

[recidive]

Any updates on this? The current Inputs.datetime behavior is very odd, and it bugs people working with data that has a lower timeframe where hours are important.

[tophtucker]

Thanks for the bump @recidive; merging now. (And then it may take a day or two for us to get the new version of inputs into the runtime and onto observablehq.com.)

[tophtucker]

@recidive Can you believe I said "a day or two" in April? This just deployed; see test cases here: https://observablehq.com/d/4303b3734fb950d8. So sorry for the delay, life intervened and we've been focused elsewhere. But we've improved our internal processes (namely, more people can publish new releases of these libraries) so this won't be such a bottleneck in the future.