fix insecure links

content/pages/ellinikes-koinotites.md

@@ -27,7 +27,7 @@ menu:
 |LUG|~~Μυτιλήνη~~|[~~mlug~~](https://groups.google.com/group/mytilene-linux-user-group)|
 |LUG|~~Πάτρα~~||[~~plug~~](https://web.archive.org/web/20150716154121/https://www.patras-lug.gr/)|
 |LUG|Πτολεμαϊδα|[plug](https://www.plug.gr/)|[forum.plug.gr](https://forum.plug.gr/)|
-|LUG|~~Σέρρες~~|[~~serlug~~](https://teiserron.gr/index.php?PHPSESSID=9484d8484536ee188336be738d23ade0&board=513.0)|
+|LUG|~~Σέρρες~~|[~~serlug~~](https://teiserron.gr/)|
 |LUG|~~Σύρος~~|[~~sylug~~](https://web.archive.org/web/20120113160631/https://cywn.dyndns.org/)|
 |Σύλλογος|~~Χανιά~~|[~~chania-lug~~](https://web.archive.org/web/20190113123512/https://www.chania-lug.gr/)|
 |Σύλλογος|~~Ζάκυνθος~~|[~~zantelug~~](https://web.archive.org/web/20110816173545/https://www.zantelug.gr/zlug/)|