improve hack/new-cluster.sh script

Within the last few days, my workflow completely broke down. After running make hack-new-kind-cluster, other commands like make hack started failing. The specific issue was an inability to push images to localhost:5000 where the registry that's connected to our kind cluster should be listening.

I'm chalking this recent breakdown up to a recent Docker Desktop upgrade I took.

After many docker system prune -af, many reboots (just to be sure), and lots of experimentation, I discovered that the inability to push to localhost:5000 only starts after the registry is connected to kind's own bridge network. Disconnect the registry from that network and ::poof::, you can push to localhost:5000 again. I cannot spot what is special about that network that is causing this issue.

So I decided to test a different approach. Instead of making the registry join kind's bridge network, I made a new bridge network of my own and joined both the registry and kind to it. Everything works with this configuration. There is no trouble pushing images to localhost:5000, nor does the kind node have any difficulty pulling images from that same registry.

This PR modifies the hack/new-cluster.sh script to implement the setup I just described.

brigadecore / brigade

improve hack/new-cluster.sh script #1872