Feat!: Upgrade Jenkins-job-builder to 6x

Jenkins Job Builder 6.0.0 is released and breaks backward
compatibility with 5.1.0.

The breaking changes with previous 5.1.0 release:

- Jobs are now expanded the same way as job templates.
- Macros without parameters are now expanded the same way as macros
  with parameters.
- Tags !include-raw: and !include-raw-escape: should now be used the
  same way in jobs and macros without parameters as they are used in
  job templates and macros with parameters.

Note: This breaks backward compatibility with older version of JJB
therefore care must be taken when upgrading the ci-man repositories.

Ref:
https://storyboard.openstack.org/#!/story/2010963
https://storyboard.openstack.org/#!/story/2010588

Issue: RELENG-5118
Change-Id: Ib9acd0b9e7c264ac3531af858431e738397833b5
Signed-off-by: Anil Belur <abelur@linuxfoundation.org>