qapi: Update flake8 config

New versions of flake8 don't like same-line comments. (It's a version
newer than what fc37 ships, but it still makes my life easier to fix it
now.)

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230215000011.1725012-2-jsnow@redhat.com>

scripts/qapi/.flake8

@@ -1,2 +1,3 @@
 [flake8]
-extend-ignore = E722  # Prefer pylint's bare-except checks to flake8's
+# Prefer pylint's bare-except checks to flake8's
+extend-ignore = E722