feat: update license

Author: SuGlider

libraries/Update/src/Updater.cpp

@@ -1,3 +1,11 @@
+/* 
+   This code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+*/
+
 #include "Update.h"
 #include "Arduino.h"
 #include "spi_flash_mmap.h"