Update site metadata

Author: marcprux

_includes/head-custom.html

@@ -5,4 +5,4 @@
 <meta name="twitter:card" content="summary" />
 <meta name="twitter:title" content="{{site.title}}" />
 <meta name="twitter:image" content="https://keepandroidopen.org/altered-deal.png" />
-<a rel="me" href="https://techhub.social/@keepandroidopen">Mastodon</a>
+<link rel="me" href="https://techhub.social/@keepandroidopen" />