bump coredns helm chart dependency to get support for imagePullSecrets

[ErikLundJensen]

Update dependency to CoreDNS from 1.15.3 to at least 1.16.7 to get support for imagePullSecrets in CoreDNS

See also https://github.com/coredns/helm/blob/master/charts/coredns/values.yaml#L13

[k0da]

We use forked chart

[ErikLundJensen]

Should I create an issue in https://github.com/AbsaOSS/coredns-helm for getting the fork updated with new version of CoreDNS?

[k0da]

yes, please

[ErikLundJensen]

I can't create an issue as AbsaOSS/coredns-helm is a fork. Let's get the original CoreDNS to implement the skipConfigMap.
I do see a PR for CoreDNS which is stuck:
coredns/helm#41

k0da could you update the PR so there are no conflicts. Then I'll then push for the review and merge of it.

[somaritane]

@ErikLundJensen I've enabled the issue creation in the AbsaOSS/coredns-helm
Not sure if all changes made there have been pushed to the upstream.
@k0da we might want to move this fork to k8gb.io org umbrella.