* Updates API version to 1.85 to permit an ``unhold`` verb
* Adds the ``deploy hold`` and ``clean hold`` provision states
to the internal state machine.
* Adds on documentation on steps to help provide greater clarity
to Ironic's users on how to utilize steps. It should be noted
this documentation also includes the power state reserved step
names from the DPU functionality patch.
* Fixes the state machine diagram. Changes type to PNG as SVG
rendering is broken due to python libraries utilized for SVG
generation which do not work on more recent Python versions.
Change-Id: I34f58f4e77e7757b89247fd64f5fcde26f679453