fix date format

Signed-off-by: William Woodruff <william@astral.sh>

Author: woodruffw

peps/pep-9999.rst

@@ -6,7 +6,7 @@ PEP-Delegate: Donald Stufft <donald@stufft.io>
 Status: Draft
 Type: Standards Track
 Topic: Packaging
-Created: 2025-09-15
+Created: 15-Sep-2025
 Post-History: `08-Aug-2025 <https://discuss.python.org/t/pre-pep-trusted-publishing-token-exchange/103067>`__
 
 Abstract