Fix incorrect PEP reference in news entry for 69.0.0

The entry referenced PEP 612 (Parameter Specification Variables), but it
should have referenced PEP 621 (Storing project metadata in
pyproject.toml) instead.

NEWS.rst

@@ -58,7 +58,7 @@ Deprecations and Removals
 - Added strict enforcement for ``project.dynamic`` in ``pyproject.toml``.
   This removes the transitional ability of users configuring certain parameters
   via ``setup.py`` without making the necessary changes to ``pyproject.toml``
-  (as mandated by :pep:`612`). (#4066)
+  (as mandated by :pep:`621`). (#4066)
 - Removed handling of ``--config-settings["--build-option"]`` in ``setuptools.build_meta``
   from build-backend API hooks *other than* ``build_wheel``.
   This was motivate by `errors caused when passing this option