Prepare for release 2.3.6

Author: kpeeters

web2/cadabra2/source/changelog.html

@@ -17,6 +17,11 @@ <h1>Change log</h1>
 </p>
 <a name="master"></a>
 <h3>github master (2.3.5)</h3>
+<ul>
+  <li>nothing yet...</li>
+</ul>
+
+<h3>2.3.6 (released 30-Dec-2020)</h3>
 <ul>
   <li>Once further change to the installation path of
   the <tt>cadabra2.so</tt> module, so that it conforms with standard
@@ -26,6 +31,9 @@ <h3>github master (2.3.5)</h3>
     the Jupyter package in Debian. </li>
   <li>Fix display of lists containing <tt>Ex</tt> objects.</li>
   <li>Fix import of Jupyter notebooks.</li>
+  <li>Fix bug related to automatic dummy index relabelling.</li>
+  <li>Fix tab-completion.</li>
+  <li>Fix build issues on recent versions of HomeBrew/macOS.</li>
 </ul>
 
 <a name="2.3.4"></a>