update URL in slack webhook (#23)

diff --git a/.travis.yml b/.travis.yml
index 729c903..c4c824b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -27,7 +27,7 @@
   webhooks:
     urls:
       # travis2slack webhook to enable DMs on openwhisk-team.slack.com to PR authors with TravisCI results
-      secure: "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"
+      secure: "NzZ1Q8KiPUezZXiIaHxsq07OLycJHOvnHvhjEtztk+XUGm+gjUKJj/OUPVLqLFGbkafORtQScDQlpnrqo1mINb4hv2XVA0ylvSvS+7nzYSzH53H4r9zT3jKRUbiagS9nVItZ4wIsRANM8MkdnBUqk1QgkKTozRih4GsDRV5dRcflLcPMSzIsx5ub0sLKI9k4alny0wpvkGx8c/pvRUFqW2U2ES262X8gbgo1FLkGYMANbNUyxh3I91SRkVTKKUKKPXTQDlFCo6QspX8lhuakt5TVE29IYGPNq4tGVhu+eHnChMrNpOrQojx0wsJTIxvyJX90JDrK6FrUe/HOJmoCitTsDFCwAk5smEcP6L1xHi9hP6zVrVEclF+8pph6KNhrgH2M0qrIZ+Lr/HhVRQ0UJK4T0T2dllUAaOQ9ERr1j3rXe/OAeMlYFiVekgCZsjQ/g64LPnZWMlDf1dHZtAI+eYYm6iWJVfyzz3EfzQQWinltu0eFVRZFskNv5+S+jsg9kIhGshB2jW329qJzevYaQH/dgn9+3kAR8IyB1o1JULAxm6PQCRPDPUTz5x4cyQhhAe5we3vOnb0TwUOEu/hLYwWDsrcMtEXLhOgazawshWZQtXh9e4lMMs8dmrsyCmiu2sFlvH5UYG9+FJVrtUyAXn8v+8OQNDanIWllJvAPG64="
 
 before_install:
 - "./tools/travis/setup.sh"