[ci skip] Update changelog

Author: petk

UPGRADING.INTERNALS

@@ -185,6 +185,8 @@ PHP 7.4 INTERNALS UPGRADE NOTES
     - Obsolescent macros AC_FUNC_VPRINTF and AC_FUNC_UTIME_NULL have been
       removed. Symbols HAVE_VPRINTF and HAVE_UTIME_NULL are no longer defined
       since they are not needed on the current systems.
+    - The disable|enable-opcache-file configure options have been removed in
+      favor of the opcache.file_cache ini directive.
 
   c. Windows build system changes