Use the daemon attribute instead of setDaemon

setDaemon was deprecated in python/cpython#25174

Fixes:
```
>>> test_tls_server("ECDHE-RSA-AES128-SHA", "-tls1")
Traceback (most recent call last):
  File "<input>", line 2, in <module>
  File "<input>", line 9, in test_tls_server
  File "/usr/lib64/python3.11/threading.py", line 1240, in setDaemon
    warnings.warn('setDaemon() is deprecated, set the daemon attribute instead',
DeprecationWarning: setDaemon() is deprecated, set the daemon attribute instead
```

test/tls/tests_tls_netaccess.uts

@@ -145,8 +145,7 @@ def test_tls_server(suite="", version="", tls13=False, client_auth=False, psk=No
     q_ = Queue()
     th_ = threading.Thread(target=run_tls_test_server, args=(msg, q_),
                            kwargs={"curve": None, "cookie": False, "client_auth": client_auth, "psk": psk},
-                           name="test_tls_server %s %s" % (suite, version))
-    th_.setDaemon(True)
+                           name="test_tls_server %s %s" % (suite, version), daemon=True)
     th_.start()
     # Synchronise threads
     q_.get()
@@ -254,8 +253,7 @@ def test_tls_client(suite, version, curve=None, cookie=False, client_auth=False,
     th_ = threading.Thread(target=run_tls_test_server, args=(msg, q_),
                            kwargs={"curve": None, "cookie": False, "client_auth": client_auth,
                                    "handle_session_ticket": sess_in_out},
-                           name="test_tls_client %s %s" % (suite, version))
-    th_.setDaemon(True)
+                           name="test_tls_client %s %s" % (suite, version), daemon=True)
     th_.start()
     # Synchronise threads
     print("Syncrhonising...")