docs: add 2.4.0 gpg signature.

Author: rouilj

doc/security.txt

@@ -133,6 +133,7 @@ with 1.6.0 have been moved and are linked below:
 
 .. rst-class:: multicol
 
+* `2.4.0 <../signatures/roundup-2.4.0.tar.gz.asc>`_
 * `2.4.0b2 <../signatures/roundup-2.4.0b2.tar.gz.asc>`_
 * `2.3.0 <../signatures/roundup-2.3.0.tar.gz.asc>`_
 * `2.3.0b2 <../signatures/roundup-2.3.0b2.tar.gz.asc>`_

website/www/signatures/roundup-2.4.0.tar.gz.asc

@@ -0,0 +1,16 @@
+-----BEGIN PGP SIGNATURE-----
+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+=xIKB
+-----END PGP SIGNATURE-----