Publish helm chart using github pages

[hemstreet]

What kind of change does this PR introduce?

This change enables you to install this chart from terraform. All it require is a new branch named gh-pages. Currently the index.yaml inside the root of this project has invalid urls and is confusing to setup.

This solves the manual process of creating releases and will produce the output like so. All on a new tag creation, it will use the chart version vs the actual tag number.

With this change, it would then let you install this chart like so:

resource "helm_release" "suspabase" {
  name       = "supabase"
  repository = "https://github.com/supabase-community/supabase-kubernetes"
  chart      = "supabase"
  version    = "0.1.3"

  namespace        = "supabase"
  create_namespace = true
  ...
}

You will still need to set values, etc.

Bug fix, feature, docs update, ...

What is the current behavior?

When running helm install via terraform, You can try to use the raw content url but the tar.gz urls are invalid

https://raw.githubusercontent.com/supabase-community/supabase-kubernetes/refs/heads/main/index.yaml

Please link any relevant issues here.
#76

Fixes this draft from April https://github.com/supabase-community/supabase-kubernetes/pull/55/files

What is the new behavior?

uses github pages to host the helm charts

Feel free to include screenshots if it includes visual changes.

Additional context

Add any other context or screenshots.

[hemstreet]

@mdluo i there anything pending on this? I saw you approved of it last week. I don't have merge access, Just trying to help push this over the finish line / be diligent about anything that is pending.