docs: Update documentation for the release of ndnSIM 2.3

Change-Id: I3d23bcf29f4858049d1040a3e421e1c7151b3ee1
Refs: #3876
diff --git a/docs/source/_templates/indexcontent.html b/docs/source/_templates/indexcontent.html
index 1595e5d..e83a04b 100644
--- a/docs/source/_templates/indexcontent.html
+++ b/docs/source/_templates/indexcontent.html
@@ -56,8 +56,9 @@
       <td width="50%" valign="top">
         <h2>ndnSIM Versions</h2>
         <div class="tile">
-          <p class="biglink"><a class="biglink" href="#">ndnSIM 2.2</a><br/>
+          <p class="biglink"><a class="biglink" href="#">ndnSIM 2.3</a><br/>
             <span class="linkdescr">latest version</span></p>
+          <p class="biglink"><a class="biglink" href="http://ndnsim.net/2.2/">ndnSIM 2.2</a><br/>
           <p class="biglink"><a class="biglink" href="http://ndnsim.net/2.1/">ndnSIM 2.1</a><br/>
           <p class="biglink"><a class="biglink" href="http://ndnsim.net/2.0/">ndnSIM 2.0</a><br/>
           <p class="biglink"><a class="biglink" href="http://ndnsim.net/1.0/">ndnSIM 1.0</a><br/>
@@ -73,10 +74,10 @@
           <p>If you are referring to ndnSIM in a published work, please cite the following papers, not just the ndnSIM website. Thank you!
           <ul>
             <li>
-              S. Mastorakis, A. Afanasyev, I. Moiseenko, and L. Zhang, &#8220;ndnSIM 2.0: A new version of the NDN simulator for NS-3,&#8221; NDN, Technical Report NDN-0028, Revision 2, 2016 (<a class="reference external" href="http://named-data.net/techreport/ndn-0028-2-ndnsim-v2.pdf">PDF</a>) (<a class="reference external" href="http://lasr.cs.ucla.edu/afanasyev/bibwiki/bibtex/399">BibTex</a>)
+              S. Mastorakis, A. Afanasyev, I. Moiseenko, and L. Zhang, &#8220;ndnSIM 2: An updated NDN simulator for NS-3,&#8221; NDN, Technical Report NDN-0028, Revision 2, 2016 (<a class="reference external" href="https://named-data.net/wp-content/uploads/2016/11/ndn-0028-2-ndnsim-v2.pdf">PDF</a>) (<a class="reference external" href="http://lasr.cs.ucla.edu/afanasyev/bibwiki/bibtex/399">BibTex</a>)
             </li>
             <li>
-            A. Afanasyev, I. Moiseenko, and L. Zhang, &#8220;ndnSIM: NDN simulator for NS-3,&#8221; NDN, Technical Report NDN-0005, 2012 (<a class="reference external" href="http://named-data.net/wp-content/uploads/TRndnsim.pdf">PDF</a>) (<a class="reference external" href="http://lasr.cs.ucla.edu/afanasyev/bibwiki/bibtex/367">BibTex</a>)
+            A. Afanasyev, I. Moiseenko, and L. Zhang, &#8220;ndnSIM: NDN simulator for NS-3,&#8221; NDN, Technical Report NDN-0005, 2012 (<a class="reference external" href="https://named-data.net/wp-content/uploads/TRndnsim.pdf">PDF</a>) (<a class="reference external" href="http://lasr.cs.ucla.edu/afanasyev/bibwiki/bibtex/367">BibTex</a>)
             </li>
           </ul>
         </div>