If `inplaceUpdate` is true, then an implementation supporting this
feature may permit tools to directly update files with `writable: true` in `InitialWorkDirRequirement`. That is, as an optimization,
files may be destructively modified in place as opposed to copied
and updated.

An implementation must ensure that only one workflow step may
access a writable file at a time. It is an error if a file which
is writable by one workflow step file is accessed (for reading or
writing) by any other workflow step running independently.
However, a file which has been updated in a previous completed
step may be used as input to multiple steps, provided it is
read-only in every step.

`Workflow` steps which modify a file must produce the modified file
as output. Downstream steps which further process the file must
use the output of previous steps, and not refer to a common input
(this is necessary for both ordering and correctness).

`Workflow` authors should provide this in the `hints` section. The
intent of this feature is that workflows produce the same results
whether or not `InplaceUpdateRequirement` is supported by the
implementation, and this feature is primarily available as an
optimization for particular environments.

Users and implementers should be aware that workflows that
destructively modify inputs may not be repeatable or reproducible.
In particular, enabling this feature implies that `WorkReuse` should
not be enabled.
