travis-ci: use proper domain for sr-dev mailing list [skip ci]

(cherry picked from commit bce1db4fce2a7cd75a8103916e1361b9c94d6f64)

.travis.yml

@@ -19,6 +19,6 @@ notifications:
     on_failure: always
   email:
     recipients:
-      - sr-dev@lists.sip-router.org
+      - sr-dev@lists.kamailio.org
     on_success: never
     on_failure: always