add whereto to gerritbot for openstack-doc
add whereto to gerritbot for openstack-doc

Announce changes to patches for whereto in openstack-doc channel.

Change-Id: I271b5a93a047f13d89c59dcb036bd99a7a045acb
Signed-off-by: Doug Hellmann <0798ebecfb7bc4dfb9d0445c2fa030eb64e1fa1c@doughellmann.com>

openstack-infra/project-config,openstack-infra/project-config