Improve pre-render workflow

[yebai]

Currently, we have two scripts (changelog and versions) that run before rendering. Let’s

• Use a Github Action step for running these scripts instead of Quarto pre-rendering
• Only run these scripts for the most recent release, and skip those for versioned docs. The changelog and version files are not linked for versioned docs from the navigation menu anyway.

This improved workflow would avoid building the changelog and version files when running Quarto locally, which could cause (minor) issues.