Fix the MAINTAINERS record for the certs/ directory

Fix the MAINTAINERS record for the certs/ directory to have the new
keyrings mailing list and also to be authoritative for the sign-file tool
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>

MAINTAINERS

@@ -2706,10 +2706,11 @@ F:	fs/ceph/
 CERTIFICATE HANDLING:
 M:	David Howells <dhowells@redhat.com>
 M:	David Woodhouse <dwmw2@infradead.org>
-L:	keyrings@linux-nfs.org
+L:	keyrings@vger.kernel.org
 S:	Maintained
 F:	Documentation/module-signing.txt
 F:	certs/
+F:	scripts/sign-file.c
 F:	scripts/extract-cert.c
 
 CERTIFIED WIRELESS USB (WUSB) SUBSYSTEM: