[Build] Update copyright year to 2024

Build-only update of copyright year. A full headers copyright year
update will be done separately.

configure.ac

@@ -6,7 +6,7 @@ define(_CLIENT_VERSION_REVISION, 99)
 define(_CLIENT_VERSION_BUILD, 0)
 define(_CLIENT_VERSION_RC, 0)
 define(_CLIENT_VERSION_IS_RELEASE, false)
-define(_COPYRIGHT_YEAR, 2023)
+define(_COPYRIGHT_YEAR, 2024)
 AC_INIT([PIVX Core],m4_join([.], _CLIENT_VERSION_MAJOR, _CLIENT_VERSION_MINOR, _CLIENT_VERSION_REVISION, m4_if(_CLIENT_VERSION_BUILD, [0], [], _CLIENT_VERSION_BUILD))m4_if(_CLIENT_VERSION_RC, [0], [], [rc]_CLIENT_VERSION_RC),[https://github.com/pivx-project/pivx/issues],[pivx],[https://www.pivx.org/])
 AC_CONFIG_SRCDIR([src/validation.cpp])
 AC_CONFIG_HEADERS([src/config/pivx-config.h])