make the main content/blog section configurable instead of hardcoded to notes

layouts/partials/scripts/utterances.html

@@ -1,6 +1,6 @@
 <script async defer
         src="https://utteranc.es/client.js"
-        data-repo="{{ .Site.Params.utterancesRepo }}"
+        data-repo="{{ .Site.Params.github }}"
         data-issue-term="og:title"
         data-label="comments"
         data-theme="github-light"