social: fix twitter url

Author: Pablo Panero

mkdocs.yml

@@ -47,7 +47,7 @@ extra:
   - type: 'github'
     link: 'https://github.com/inveniosoftware'
   - type: 'twitter'
-    link: 'https://twitter.com/invenio'
+    link: 'https://twitter.com/inveniosoftware'
   - type: 'comments'
     link: 'https://invenio-talk.web.cern.ch/c/projects/invenio-rdm'
   - type: 'globe'