fix: drop Python 3.10 and add Python 3.15 support

gns3server/server.py

@@ -255,9 +255,9 @@ class Server:
         else:
             log.info(f"Compute authentication is enabled with username '{config.Server.compute_username}'")
 
-        # we only support Python 3 version >= 3.9
-        if sys.version_info < (3, 9, 0):
-            raise SystemExit("Python 3.9 or higher is required")
+        # we only support Python 3 version >= 3.11
+        if sys.version_info < (3, 11, 0):
+            raise SystemExit("Python 3.11 or higher is required")
 
         log.info(
             f"Running with Python {sys.version_info[0]}.{sys.version_info[1]}.{sys.version_info[2]} and has PID {os.getpid()}"