CHANGELOG.md: add note about deprecations

Fix these errors from Hugo:

    ERROR deprecated: .Site.GoogleAnalytics was deprecated in Hugo v0.120.0 and will be removed in Hugo 0.134.0. Use .Site.Config.Services.GoogleAnalytics.ID instead.
    ERROR deprecated: .Site.DisqusShortname was deprecated in Hugo v0.120.0 and will be removed in Hugo 0.134.0. Use .Site.Config.Services.Disqus.Shortname instead.

layouts/_default/baseof.html

@@ -31,7 +31,7 @@
       {{ printf `<link rel="%s" type="%s" href="%s" title="%s" />` .Rel .MediaType.Type .Permalink $.Site.Title | safeHTML }}
     {{ end -}}
 
-    {{ if .Site.GoogleAnalytics }}
+    {{ if .Site.Config.Services.GoogleAnalytics.ID }}
     {{ partial "cookie-consent.html" . }}
     {{ end }}
 

layouts/_default/single.html

@@ -83,7 +83,7 @@
   </ul>
   {{ end }}
 
-  {{ if or (ne ($.Param "sharingicons") false) (.Site.DisqusShortname) }}
+  {{ if or (ne ($.Param "sharingicons") false) (.Site.Config.Services.Disqus.Shortname) }}
   <hr>
   <footer>
 
@@ -91,7 +91,7 @@
   {{ partial "sharing-icons.html" . }}
   {{ end }}
 
-  {{ if and (.Site.DisqusShortname) (ne .Params.comments false) }}
+  {{ if and (.Site.Config.Services.Disqus.Shortname) (ne .Params.comments false) }}
   {{ template "_internal/disqus.html" . }}
   {{ end }}
   </footer>

layouts/partials/cookie-consent.html

@@ -28,7 +28,7 @@ Haven.create({
         {
             name: 'google-analytics',
             options: {
-                    id: {{ .Site.GoogleAnalytics }},
+                    id: {{ .Site.Config.Services.GoogleAnalytics.ID }},
             },
             purposes: ['analytics'],
             inject: true,