fix: compatibility with newer Hugo version

[paleboot]

Hi, first of all thanks for the amazing site :D

While traversing I've found some seemingly broken sections of the page, e.g.

• https://trunkbaseddevelopment.com/publications/
• some embedded videos in https://trunkbaseddevelopment.com/game-changers/

After tinkering around in local with a newer Hugo version (v0.119.0), I found that Hugo changed their markdown parse to https://github.com/yuin/goldmark, where they

By default, goldmark does not render raw HTML or potentially dangerous links. With this option, goldmark renders such content as written.

Assuming that the ones hosted on Netlify uses a version that changed Hugo's default parser to goldmark, this PR toggles the unsafe config to true to allow raw HTML in markdown.

In addition to that I had to fix the theme in accordance to newer Hugo's template API.