Update syntax highlighting for zola 0.22.0 compat

A breaking change was introduced in 0.22.0, details here:

https://github.com/getzola/zola/blob/master/CHANGELOG.md#0220-2026-01-09

Replace our previous `inspired-github` theme with new `github-light`
theme which seems like a sane enough replacement.  I'm not sure we're
even using this in any existing capacity today.

Signed-off-by: John Eckersberg <jeckersb@redhat.com>

Author: jeckersb

config.toml

@@ -36,16 +36,15 @@ generate_robots_txt = true
 #exclude_paginated_pages_in_sitemap
 
 [markdown]
-# Whether to do syntax highlighting
-# Theme can be customised by setting the `highlight_theme` variable to a theme supported by Zola
-highlight_code = true
-highlight_theme = "inspired-github"
 render_emoji = true
 external_links_class = "external"
 external_links_target_blank = true
 external_links_no_referrer = true
 #insert_anchor_links = "left"
 
+[markdown.highlighting]
+theme = "github-light"
+
 [extra]
 # Put all your custom variables here
 juice_logo_name = "bootc"