Add IPv6 support

[phil-scale]

What does this PR do?

Adds IPv6 support to the DogStatsd class

Description of the Change

Adds a method to detect if a hostname can be resolved as an IPv6 hostname, and if so, uses the socket.AF_INET6 family of sockets

Alternate Designs

Possible Drawbacks

Verification Process

Before PR:

>>> from datadog.dogstatsd.base import DogStatsd
>>> DogStatsd._get_udp_socket("0.0.0.1", 8126)
<socket.socket fd=4, family=AddressFamily.AF_INET, type=SocketKind.SOCK_DGRAM, proto=0, laddr=('10.254.0.78', 57605), raddr=('0.0.0.1', 8126)>
>>> DogStatsd._get_udp_socket("::", 8126)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/opt/miniconda3/envs/hmi/lib/python3.8/site-packages/datadog/dogstatsd/base.py", line 544, in _get_udp_socket
    sock.connect((host, port))
socket.gaierror: [Errno 8] nodename nor servname provided, or not known

After:

>>> from datadog.dogstatsd.base import DogStatsd
>>> DogStatsd._get_udp_socket("0.0.0.1", 8126)
<socket.socket fd=4, family=AddressFamily.AF_INET, type=SocketKind.SOCK_DGRAM, proto=0, laddr=('10.254.0.78', 57605), raddr=('0.0.0.1', 8126)>
>>> DogStatsd._get_udp_socket("::", 8126)
<socket.socket fd=5, family=AddressFamily.AF_INET6, type=SocketKind.SOCK_DGRAM, proto=0, laddr=('::1', 63924, 0, 0), raddr=('::1', 8126, 0, 0)>

Additional Notes

Release Notes

Review checklist (to be filled by reviewers)

• Feature or bug fix MUST have appropriate tests (unit, integration, etc...)
• PR title must be written as a CHANGELOG entry (see why)
• Files changes must correspond to the primary purpose of the PR as described in the title (small unrelated changes should have their own PR)
• PR must have one changelog/ label attached. If applicable it should have the backward-incompatible label attached.
• PR should not have do-not-merge/ label attached.
• If Applicable, issue must have kind/ and severity/ labels attached at least.

[github-actions]

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[nextmat]

I'm running into issues with IPv6 support as well, any change of getting this merged?