Update legal notices for 2023

LICENSE

@@ -1,5 +1,5 @@
 The Mempool Open Source Project
-Copyright (c) 2019-2022 The Mempool Open Source Project Developers
+Copyright (c) 2019-2023 The Mempool Open Source Project Developers
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of (at your option) either:

frontend/src/app/components/about/about.component.html

@@ -352,7 +352,7 @@
 
   <div class="copyright">
     <div class="title">
-      Copyright &copy; 2019-2022<br>
+      Copyright &copy; 2019-2023<br>
       The Mempool Open Source Project
     </div>
     <p>