Code Conventions change: A new package now goes in the same change as the code that needs it

web/CODE_CONVENTIONS.md

@@ -369,7 +369,7 @@ external keep its spelling (`Authorization`, CSS `color`).
   different code. The app's own dependencies use `^` ranges, held by the
   lock file.
 - A new or upgraded package is a release at least two weeks old, and is
-  added deliberately, in its own change.
+  added deliberately, in the same change as the code that needs it.
 
 ## Tests