ci: multiple ruby configuration fixes

[baywet]

this PR drops a bunch of outdated gems that made it difficult / impossible to run the site locally. It also switches from automatic publishing to workflow based (we'll need to flip the switch in the settings) and adds a vscode task to run the container

[Copilot]

Pull request overview

This PR modernizes the Ruby/Jekyll toolchain for the site to improve local development and updates CI/CD to deploy the site via a dedicated GitHub Actions Pages workflow.

Changes:

• Replace the github-pages gem stack with direct jekyll ~> 4.4 dependencies and refresh the lockfile (Bundler 2.6.x).
• Add a GitHub Actions workflow to build and deploy the Jekyll site to GitHub Pages.
• Improve local dev ergonomics via updated Docker instructions, a VS Code task, and ignoring the local Bundler cache (.bundle/).

Reviewed changes

Copilot reviewed 4 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
Gemfile.lock	Updates dependency resolution to Jekyll 4.4.x and newer supporting gems; updates Bundler version.
Gemfile	Switches from github-pages to direct jekyll + plugin/theme gems for local dev compatibility.
CONTRIBUTING.md	Updates Docker-based dev instructions and documents the new VS Code task.
.vscode/tasks.json	Adds a VS Code task to run Jekyll via Docker with a local gem cache path.
.gitignore	Ignores .bundle/ created by the Docker/local bundler cache path.
.github/workflows/deploy-pages.yml	Adds a Pages build+deploy workflow using Ruby setup, Jekyll build, and Pages artifact/deploy actions.

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[ralfhandl]

Running locally works on macOS
Running via Docker works
VS Code task works

Haven't checked the new publishing workflow, not my area of expertise.

[baywet]

Thanks for confirming all those platforms @ralfhandl
I've on my side tested windows, and vscode in windows.

[ralfhandl]

Did you test the new publishing workflow in a fork of this repo?

[baywet]

@ralfhandl I can't, we need to change a setting on the repo as far as I understand, and I don't have those permissions

[ralfhandl]

If you fork the repo, you have the permissions in your fork to deploy to the default GH-pages site. And this is a good test of what you have to change in the GH-pages settings.

[ralfhandl]

I've created a fork that uses deploy-pages.yml to publish the website, the result is unsatisfactory: https://ralfhandl.github.io/spec.openapis.org/.

Not my area of expertise, so I won't dig into why it looks so weird.

[baywet]

@ralfhandl this is cause by the combination of the facts:

• we had absolute urls for the assets
• your fork test is serving under a sub-path

I've pushed a fix, could you merge that into your fork please?

(not setting up my own fork because I have a blog at https://baywet.github.io and I'm afraid it'll mess it up)

[ralfhandl]

Looks good now on https://ralfhandl.github.io/spec.openapis.org/

[ralfhandl]

@baywet Do you want to resolve the Copilot review comments?