Automatically update custom nginx data container with new nginx versions

[mpstefan]

As a user of NKG
I want the data plane image to be automatically updated when nginx is updated
So that the data plane for NKG always includes the latest release of nginx.

Acceptance

• When the layers of the nginx release change from what we used to build our nginx data container, our nginx data container is updated and published with the updated nginx image.
• The updated NKG image maintains the same version.
• Document the NKG readme how our release image for the same version can change and under what circumstances it will change.

[mpstefan]

Blocked by #798

[mpstefan]

Kubernetes Ingress Controller reference: https://github.com/nginxinc/kubernetes-ingress/blob/main/.github/workflows/update-docker-images.yml

[mpstefan]

We need to determine how this change affects our SBOM for our nginx data container.