[bug] Issues closed at the end of a sprint don't get marked as completed #21
Description
GitHub stores issue create/close dates in UTC, but this project often uses the local time of the user running it. Ignoring timezone info, this often means that the GitHub create/close dates appear in the future, which can cause problems like the one reported in #17 or this one where closed issues weren't getting counted in point totals because their UTC time make it look like they closed the day after.
Handling of time needs to work better to cover these edge cases.