shipit/api: fix product details links (#1976)
shipit/api: fix product details links (#1976)

Use relative paths to the current folder instead of relative paths to
the root directory.
mozilla-releng/services,La0/mozilla-relengapi,La0/mozilla-relengapi,mozilla-releng/services,mozilla-releng/services,La0/mozilla-relengapi,mozilla-releng/services,La0/mozilla-relengapi