Add theme meta tag

layouts/partials/paige/metas.html

@@ -26,6 +26,7 @@
     <meta content="{{ (resources.Get `browserconfig.xml` | resources.ExecuteAsTemplate `browserconfig.xml` .).RelPermalink }}" name="msapplication-config">
 {{ end }}
 
+<meta content="https://github.com/willfaught/paige" name="theme">
 <meta content="{{ $page.Param `paige.color` | default `#0d6efd` }}" name="theme-color">
 <meta content="width=device-width, initial-scale=1" name="viewport">