Feat!: Update JJB version to 6x

Feat!: Update JJB version 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.
- Update pre-commit dependencies

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

NOTE: Set the var "JJB_VERSION" to "6.0.0" at the GH orginazation
level for GHA JJB Verify to pick up the latest version of JJB.

Issue: LF-JIRA RELENG-5119
Change-Id: I48f25c2e3153d93fed5c69123652513258653437
Signed-off-by: Anil Belur <abelur@linuxfoundation.org>