services: guix: Authorize the key for bayfront.guixsd.org.

* gnu/services/base.scm (%default-authorized-guix-keys): Add
"bayfront.guixsd.org".

gnu/services/base.scm

@@ -1332,7 +1332,8 @@ (define (hydra-key-authorization key guix)
 
 (define %default-authorized-guix-keys
   ;; List of authorized substitute keys.
-  (list (file-append guix "/share/guix/hydra.gnu.org.pub")))
+  (list (file-append guix "/share/guix/hydra.gnu.org.pub")
+        (file-append guix "/share/guix/bayfront.guixsd.org.pub")))
 
 (define-record-type* <guix-configuration>
   guix-configuration make-guix-configuration