updated links

data/sidebar/links/hellug.json

@@ -4,5 +4,6 @@
     {"name": "Photos", "url": "https://photos.hellug.gr"},
     {"name": "Λίστες", "url": "https://lists.hellug.gr"},
     {"name": "Αγγελίες", "url": "https://ads.hellug.gr"},
+    {"name": "linux.gr", "url": "https://www.linux.gr"},
     {"name": "Πλανήτης ΕΛΛΑΚ", "url": "https://planet.hellug.gr"}
 ]