Co-authored-by: Ross McFarland <ross@github.com>

DNSimple does not handle NULL SRV records correctly (either via
their web interface or API).  Flag to end user if attempted.

Issue noted with DNSimple support 2020-12-09

Thanks to @jdgri for assisting with API tests to confirm support

Thanks to @pwaring for assisting with API tests to confirm support,
and reaching out to Mythic Beasts to obtain a fix

Thanks to @actazen for assisting with API tests to confirm support

Thanks to @yzguy for assisting with API tests to confirm support

Thanks to @yzguy for assisting with API tests to confirm support

Addresses issues with changing between A, AAAA and CNAME records in
both directions with the Cloudflare API

See also: github/octodns#507
See also: github/octodns#586
See also: github/octodns#587

This change improves the process for checking for AzureDNS zones by using the known set and not relying upon custom error handling.

Since the provider already fetches the zones, octodns doesn't need to make a second call to check for the existence of the zone - _populate_zones already does that for us.

Signed-off-by: Marc 'risson' Schmitt <marc.schmitt@risson.space>

cc #84 #628

Use fqdn package to help verify if the record value is really valid.

The original behavior will treat value like `_.` or `.` be a valid
record, which is strange, and the real world may not have those use
cases at all.

The RFC documents are pretty long, as I didn't read them all or enough
to tell should it be valid or not by the spec, so I opened issue #612 to
discuss this case and got a positive response from the main maintainer
to have the change.

Close #628

This commit strips any superfluous -alphaN (or beta or rc) from the
version number's minor number so it can be cast to an int. This will
allow octodns to sync to/from PowerDNS pre-releases.

Closes #626