IPV6 Addresses are generally case insensitive but it is recommented to
store them as lowercase (https://tools.ietf.org/html/rfc5952#section-4.3)
When Terraform didn't store them as LowerCase, we got the following
error when using in DNS records:
```
-/+ digitalocean_record.web6
domain: "mydomain.com" => "mydomain.com"
fqdn: "web02.in.mydomain.com" => "<computed>"
name: "web02.in" => "web02.in"
port: "0" => "<computed>"
priority: "0" => "<computed>"
type: "AAAA" => "AAAA"
value: "2a03:b0c0:0003:00d0:0000:0000:0b66:6001" => "2A03:B0C0:0003:00D0:0000:0000:0B66:6001" (forces new resource)
weight: "0" => "<computed>"
```
There was no need for this to be the case. We now enforce lowercase on both state and also when responses are returned from the API
eac6546e33