Add jenkins plugin `parameterized-trigger` back
Add jenkins plugin `parameterized-trigger` back

During [platform alert
PR](https://github.com/alphagov/multicloud-deploy/pull/29) we
accidentaly removed the entry to install the plugin
parameterized-trigger in jenkins. Because that, the deploy demo job fails.

alphagov/multicloud-deploy,alphagov/multicloud-deploy,alphagov/multicloud-deploy