chore: Release package async-acme version 0.6.0

updated rustls, rcgen and the hyper example (#10)

* updated rustls, rcgen, http client and the hyper example
* added some basic tests

Merge pull request #9 from User65k/v4

V4

Merge pull request #7 from User65k/dep

dependency update

fix IoError import

removed debug print

fixed build img paths