Add missing header.

Update build image to Ruby version 2 instead of latest fix the issue (see https://gitlab.com/pages/jekyll/-/issues/40)

Initial version without notes about logging configuration.

Image is not used directly by the blog but only when publishing on dev.to.

Illustration for streaming using OBS article.

- Favicon in various format
- Minima theme customization for head in order to include the favicon

- New post how to stream live prerecorded videos on YouTube with OBS
- Add sitemap Jekyll plugin for better indexing
- Add SEO Jekyll plugin for better indexing