Fix install and add instructions

[acrogenesis]

The makefile was failing because go get is deprecated.

Once deploy the ghcr.io/coderanger/migrations-operator:latest image was causing trouble as seen in #5

[dacox]

@acrogenesis 👋 I know it's been a while, but I've been playing with this project this afternoon.

I've got it most of the way there, but the API server seems to always return 400 which is causing the waiter containers to crash.

Any ideas? I'm reading through the code trying to figure it out - using the main image as well.

EDIT

Ok, its obviously because my curl code has no payload.

However, the waiter container is having

"2024/08/13 23:17:14 Error while polling: Post "http://migrations-operator-api-service.migrations-operator-system.svc:5000/api/ready": dial tcp 10.28.9.169:5000: connect: connection refused"

I presume this is related to the fact that we also inject the istio proxy in our pods, but am not sure