Only use derived variables

docs/_includes/elements/github.html

@@ -1,4 +1,4 @@
-<a class="button bd-github-button" href="https://github.com/users/jgthms/sponsorship" target="_blank">
+<a class="button bd-github-button" href="{{ site.data.meta.sponsorship_url }}" target="_blank">
   <span class="icon">
     <i class="fas fa-heart"></i>
   </span>

docs/_includes/elements/patreon.html

@@ -1,4 +1,4 @@
-<a class="bd-patreon-button" href="https://www.patreon.com/jgthms" target="_blank">
+<a class="bd-patreon-button" href="{{ site.data.meta.patreon_url }}" target="_blank">
   {%
     include elements/responsive-image.html
     path="become-a-patron"

docs/_includes/index/partnrs.html

@@ -1,7 +1,7 @@
 <section class="bd-partnrs-list">
   <div class="bd-partner bd-is-sponsor">
     <p class="bd-partner-title has-text-centered">
-      Bulma is thankful to its <a href="https://www.patreon.com/jgthms" target="_blank">Patreon sponsors</a>
+      Bulma is thankful to its <a href="{{ site.data.meta.patreon_url }}" target="_blank">Patreon</a> and <a href="{{ site.data.meta.sponsorship_url }}" target="_blank">GitHub sponsors</a>
     </p>
 
     <div class="bd-partner-sponsors">
@@ -25,7 +25,7 @@
     </div>
 
     <p class="has-text-centered" style="margin-top: 1.5rem;">
-      <a class="button is-primary is-medium" href="https://www.patreon.com/jgthms" target="_blank">
+      <a class="button is-primary is-medium" href="{{ site.data.meta.sponsorship_url }}" target="_blank">
         Become a sponsor
       </a>
     </p>