add IPv6 support for statsd hostnames

[Tianwei-She]

When DD_AGENT_HOST is set to an IPv6 address, like 3b12:fb33:0:10::f262, statsd doesn't work, and a warning message shows in logs: WARNING:datadog.dogstatsd:Error submitting packet: [Errno -9] Address family for hostname not supported, dropping the packet and closing the socket.

[github-actions]

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[nextmat]

Related PR here: #783