Update CODEOWNERS

Co-authored-by: Pradyun Gedam <pradyunsg@gmail.com>

Author: jaimergp

.github/CODEOWNERS

@@ -678,6 +678,7 @@ peps/pep-0799.rst  @pablogsal
 peps/pep-0800.rst  @JelleZijlstra
 peps/pep-0801.rst  @warsaw
 peps/pep-0802.rst  @AA-Turner
+peps/pep-0804.rst  @pradyunsg
 # ...
 peps/pep-2026.rst  @hugovk
 # ...