Add missing date in scientific publications related to Orekit

publications.html

@@ -29,7 +29,7 @@ layout: default_orekit
   <li>
     <p><span class="fa-li fa-lg fa fa-gears"></span><a href="">Automatic differentiation for propagation of orbit uncertainties in Orekit</a><br/>
       Andrea Antolino (CS), Luc Maisonobe (CS)<br/>
-      Stardust Conference</p>
+      November 2016 – Stardust Conference</p>
   </li>
   <li>
     <p><span class="fa-li fa-lg fa fa-gears"></span><a href="https://www.researchgate.net/publication/283292056_VALIDATING_SHORT_PERIODICS_CONTRIBUTIONS_IN_A_DRAPER_SEMI-ANALYTICAL_SATELLITE_THEORY_IMPLEMENTATION_THE_OREKIT_EXAMPLE">Validating short periodics contributions in a draper semi-analytical satellite theory implementation: the Orekit example</a><br/>