PEP 545: Remove myself from code owners (#5001)

Add Stan instead :-)

Co-authored-by: Stan Ulbrych <stan@python.org>

Author: vstinner

.github/CODEOWNERS

@@ -412,7 +412,7 @@ peps/pep-0541.rst  @ambv
 # peps/pep-0542.rst
 peps/pep-0543.rst  @tiran
 peps/pep-0544.rst  @ilevkivskyi @ambv
-peps/pep-0545.rst  @JulienPalard @methane @vstinner
+peps/pep-0545.rst  @JulienPalard @methane @StanFromIreland
 peps/pep-0546.rst  @vstinner
 peps/pep-0547.rst  @encukou
 peps/pep-0548.rst  @bitdancer