en: introduction: Update the copyright dates

* src/en/sections/introduction.tex: Update the copyright dates.

src/en/sections/introduction.tex

@@ -116,7 +116,7 @@ \section*{Source Code}
 \section*{License}
 \addcontentsline{toc}{section}{License}
 
-Copyright © 2016-2024 Artyom ``avp'' Poptsov
+Copyright © 2016-2025 Artyom ``avp'' Poptsov
 <\href{mailto:[email protected]}{[email protected]}>.
 
 The rights to the third party materials that are used in this book are belong to