Pass list to update_record not single address

[kdienes]

There is code in update_record to detect a single item being passed:

if not isinstance(values, collections.abc.Sequence): values = (values,)

But since the IPv4 record is a string:

>>> isinstance('aaa', collections.abc.Sequence)

True

we don't get a very good error message.

I wasn't able to decide if I thought update_record should accept an IPv4Address or how to best fix the isinstance(), so I took the easy way out.