add link to GH discussions & remove flattr integration

Author: Martin Zimmermann

docs/index.html

@@ -47,14 +47,12 @@ <h2>Links</h2>
     <h2>Help</h2>
     <p>
         Join <code>#isso</code> on <a href="https://libera.chat/">Libera.Chat</a>
-        or open an issue on <a href="https://github.com/posativ/isso/issues">GitHub</a>.
+        or open an issue on <a href="https://github.com/posativ/isso/discussions">GitHub</a>.
     </p>
     <h2>Contribute</h2>
     <p>
-        <a href="{{ pathto('contribute') }}">Write Code</a>,
-        <a href="https://www.transifex.com/projects/p/isso/">Translate</a> or
-        <a href="https://flattr.com/thing/2059355/posativisso-on-GitHub">Flattr
-        <img src="{{ pathto('_static/flattr.png', 1) }}" alt="Flattr icon"/></a>.
+        <a href="{{ pathto('contribute') }}">Write Code</a> or
+        <a href="https://www.transifex.com/projects/p/isso/">Translate</a>
     </p>
 
     {% include "searchbox.html" %}