use fsnotify instead of polling for autoreload

[cyberhck]

Describe the feature

configor should reload config when the file changes and not poll it every once in a while.

Motivation

Currently, it does polling, if I do it too aggressively it calls my function too often, if not, then my credentials are rotated, but I won't know about it.

A much nicer API would be to use fsnotify instead. It has good support and it only calls if the file has changed.

Related Issues

[cyberhck]

hey everyone, we're happy to send a PR IF you guys will review and accept.

[cyberhck]

@jinzhu is this project still maintained? Looks like there's literally a PR which solves this issue and there has been no comments from you.