Binder link typo

Author: r-ford

_config.yml

@@ -52,7 +52,7 @@ sphinx:
           icon: fab fa-youtube-square
           type: fontawesome
       launch_buttons:
-        binderhub_url: https://binder.mypythia.org
+        binderhub_url: http://binder.mypythia.org
         notebook_interface: jupyterlab
       extra_navbar: |
         Theme by <a href="https://projectpythia.org">Project Pythia</a>.<br><br>