Release Notes in Github Release Page

[mrclrchtr]

We use Renovate to update dependencies. The update PR does not contain the changelog from artifacthub, because it is not able to do this atm: renovatebot/renovate#13385

So it would be nice to have the release changelog directly in release notes to be parable for renovate bot and to save time manually checking the chages.

Here is the same problem with a solution, how it could work: argoproj/argo-helm#1721