DOKS link is broken in podinfo-example/README.md

[JayWStapleton]

Should be: https://docs.digitalocean.com/products/kubernetes/getting-started/quickstart/
Currently is:
A [DOKS](https://docs.digitalocean.com/products/kubernetes/quickstart) cluster configured and running.

[adamkdean]

Noticed this took, in the doks-example, with https://docs.digitalocean.com/products/kubernetes/quickstart/ being 404, linked too from the page you're given when it's up and running.