ploftness-tesla

Add support for the reject_tokens_expiring_in_less_than option.

2

This is a followup pull request, implementing the [simplified approach](https://github.com/Keats/jsonwebtoken/issues/365#issuecomment-1910186315) discussed on https://github.com/Keats/jsonwebtoken/issues/365.

Add support for negative leeway values

7

I use `jsonwebtoken` as part of a client application. During the course of development, I have encountered two issues with how token expiration is handled: 1. The [Validation::get_current_timestamp()](https://github.com/Keats/jsonwebtoken/blob/193eb8de9e06a6a3927b0fe69a7c4ddaebe1ca50/src/validation.rs#L145-L158) method truncates...