Include logo on github pages (#747)

Author: mknaranja

docs/index.html

@@ -60,7 +60,7 @@
   <div id="header" style="width:100%; background-color:#FFFFFF; margin:0px; position:fixed; z-index:6;">
 
     <div id="header_left" style="padding-left:20px; padding-top:0px; width:30%; position:relative; float:left;">
-      <img src="memilio-small.png" width="350" height="114" alt="MEmilio-Logo">
+      <img src="https://github.com/DLR-SC/memilio/blob/main/docs/memilio-small.png" width="350" height="114" alt="MEmilio-Logo">
     </div>
     <div id="header_right" style="padding-left:20px; padding-top:40px; width:65%; position:relative; float:right;">
       <div class='menu_div'><a class='menu' href='index.html#start'>Start</a></div>
@@ -140,4 +140,4 @@ <h1>MEmilio - a high performance Modular EpideMIcs simuLatIOn software</h1>
 
 </body>
 
-</HTML>
+</HTML>