update year to 2025 in copyright.tex (pingcap#19879) (pingcap#19883)

Author: ti-chi-bot

templates/copyright.tex

@@ -1,4 +1,4 @@
 
 \noindent \rule{\textwidth}{1pt}
 
-© 2024 PingCAP. All Rights Reserved.
+© 2025 PingCAP. All Rights Reserved.