Add very basic example for mqtt tls

micropython/umqtt.simple/example_pub_tls.py

@@ -0,0 +1,26 @@
+from umqtt.simple import MQTTClient
+
+# Test reception e.g. with:
+# mosquitto_sub -t foo_topic
+
+
+def main(server="localhost"):
+    # NOTE: Checking server certificate is DISABLE
+    ssl_params = {"server_hostname": server}
+    c = MQTTClient(
+        "umqtt_client",
+        server=server,
+        port=8883,
+        user="<username>",
+        password="<password>",
+        keepalive=60,
+        ssl=True,
+        ssl_params=ssl_params,
+    )
+    c.connect()
+    c.publish(b"foo_topic", b"hello")
+    c.disconnect()
+
+
+if __name__ == "__main__":
+    main()