Trello for Slack app shows a due date in UTC in card link previews

Issue Summary

Trello for Slack app is showing due dates in UTC as opposed to the user's locally selected time zone. Here's an example of a post from Trello to a channel in Slack with a due date of 22 August, 7:45 PM PDT:

Pacific Daylight Time is seven hours behind UTC, which is being reflected here.

Steps to Reproduce

1. Copy Trello card URL.
2. Paste it into any Slack channel to see the preview.

Expected Results

The due date should be in the user's locally selected timezone.

Actual Results

The sure date is in UTC.

Workaround

No workaround.