[Docs]: provide sample docker-bake.override.hcl file

[smiyc]

since I'm creating my images manually I'm working on an override file

I managed to create the following override file

variable "environment" {
  default = "production"
}

variable "registry" {
  default = "your.repo.url"
}

fullname = ( environment == "testing") ? "${registry}/xxx/yyyy/cnpg" : "${registry}/xxx/zzzz/cnpg"

That's working fine, but I can't create an override for the target matrix.

What I want to achieve is to build

• standard images
• for all pgVersions
• based on bookworm for
• platform linux/amd64

1. how would such target matrix override look like
2. would you accept an sample override PR?