Update footer to point to sphinx_ansible_theme (#23)

sphinx_ansible_theme/footer.html

@@ -57,7 +57,11 @@
   </div>
 
   {%- if show_sphinx %}
-  {% trans %}Built with <a href="http://sphinx-doc.org/">Sphinx</a> using a <a href="https://github.com/rtfd/sphinx_rtd_theme">theme</a> provided by <a href="https://readthedocs.org">Read the Docs</a>{% endtrans %}.
+  {% trans %}Built with <a href="https://www.sphinx-doc.org/">Sphinx</a>
+  using a
+  <a href="https://pypi.org/project/sphinx-ansible-theme/">theme</a>
+  created by <a href="https://github.com/ansible-community">Ansible
+  Project and Contributors</a>{% endtrans %}.
   {%- endif %}
 
   {%- block extrafooter %} {% endblock %}