Update LICENSE copyright date in manual.

Author: rdzman

docs/MIPS-manual.pdf

@@ -22,7 +22,7 @@ Pre-release
   - `docs/relnotes/MIPS-Release-Notes-#.#.md`
   - `docs/src/MIPS-manual/MIPS-manual.tex`
     - title page
-    - copyright
+    - copyright (front page and LICENSE text)
     - Appendix C Release History
     - `\mipsver` (update `\mpver`, `\mptestver`, `\mpomver`, `\mostver` too)
   - Sphinx docs

docs/other/MIPS-Release-Checklist.md

@@ -275,7 +275,7 @@ \subsection{License and Terms of Use}
 ~\cite{bsd}. The full text of the license can be found in the \code{LICENSE} file at the top level of the distribution or at \url{https://github.com/MATPOWER/mips/blob/master/LICENSE} and reads as follows.
 
 \begin{Notice}
-Copyright (c) 1996-2016, Power Systems Engineering Research Center
+Copyright (c) 1996-2024, Power Systems Engineering Research Center
 (PSERC) and individual contributors (see AUTHORS file for details).
 All rights reserved.