Make gh-pages branch lightweight

[mjtrangoni]

Hi @qrkourier,

I found out the gh-pages branch here is a clone of the main branch, but actually it is not necessary, and only needs to have the index.yaml, and the README.md file. OTOH, the index.yaml does not need to be present at main.

[qrkourier]

I think you're correct on both points. It might be possible to go back to a lightweight gh-pages branch now.

I had intentionally duplicated those things to both because it was necessary to perform Helm indexing locally when the index was unintentionally destroyed while I was improving the packaging and release CI.

The automation still has a flaw that sometimes forces me to bump a chart version to force a release. I customized a number of Actions for this repo for things like Helm Docs.