Update website URL

Author: kinkie

_config.yml

@@ -1,9 +1,8 @@
 title: "Squid Programming Guide"
-description: "Squid Web Cache programmers' guide"
-url: "https://programming-guide.squid-cache.org/"
+description: "Squid Web Cache code reference"
+url: "https://code-reference-cache.org"
 plugins:
   - jekyll-optional-front-matter
   - jekyll-relative-links
   - jekyll-titles-from-headings
-
-# - jekyll-sitemap
+  - jekyll-sitemap