Add links to feeds for the blog + edge blog

Let's have a nice link to the RSS feeds here:

• https://postmarketos.org/blog/
• https://postmarketos.org/edge/

added difficulty::easy help wanted labels

mentioned in merge request !259 (merged)

By Oliver Smith on 2024-04-18T21:58:24

mentioned in merge request !264 (closed)

By Oliver Smith on 2024-05-12T16:31:26

this was done as part of the redesign :)

By Oliver Smith on 2024-09-29T16:23:38

closed