goldpinger does not support v6 ping

**Describe the bug**
I am trying to use goldpinger to test ipv6 connectivity between pods in Azure. I add "IP_VERSIONS" to my deployment yaml file:
```
spec:
containers:
- name: goldpinger
env:
- name: HOST
value: "0.0.0.0"
- name: PORT
value: "8080"
**- name: IP_VERSIONS
value: "6"**

When I start testing, I found from goldpingerClient to get clusterState, it does not contain ipv6 address and it only does ipv4 ping. When I read goldpinger library, I see podResult only takes ipv4 address, so it will not do ipv6 test for podResult:
https://github.com/bloomberg/goldpinger/blob/master/pkg/goldpinger/pinger.go#L77

Can anyone help check if we already support this feature or not and if so, how we can use it?

Thanks!

**To Reproduce**
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4. See error

**Expected behavior**
ipv6 ping should get executed

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**Environment (please complete the following information):**
- Operating System and Version: [e.g. Ubuntu Linux 22.04]
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**Additional context**
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Start with pkg/goldpinger/pinger.go around the referenced podResult handling, then trace how IP_VERSIONS is read and how goldpingerClient obtains clusterState. Verify whether IPv6 addresses are collected and passed into ping checks. Done means IPv6 ping executes and its result appears in the cluster state when IP_VERSIONS is set to 6.

Written by the indexing model from the issue text.