Fix: Correct the date format to 24h (coscine/issues#2097)

src/Logging/AnalyticsLogObject.cs

-using System;
+using System;
 using System.Collections.Generic;
 
 namespace Coscine.Logging
@@ -478,7 +478,7 @@ namespace Coscine.Logging
 
         private static string FormatTimestamp(DateTime timestamp)
         {
-            string formattedDateTime = string.Format("{0:yyyy-MM-dd hh:mm:ss.fff}", timestamp);
+            string formattedDateTime = string.Format("{0:yyyy-MM-dd HH:mm:ss.fff}", timestamp);
             return formattedDateTime;
         }
     }