4.0.0 Sat, Jul 1, 2023
* Bump major version due to incompatible change
* Remove class DnsAsyncRequest, asyncore is removed from Python 3.12 and it
would require a substial rewrite - If you need async DNS, use aiodns
instead. (LP: #2003329)
* Switch build system from setuptools with setup.py to flit
* If /etc/resolv.conf, assume DNS server is '127.0.0.1', this changes the
existing behavior - in previous releases there would be a
FileNotFoundError.