Add new requirements section, deprecate runtime

[jdidion]

In the 3/10/23 governance call we decided that, rather than backport the changes to runtime that currently appear in the development version, we will instead deprecate the runtime section and add a new requirements section that will have the semantics of the development runtime section.

[jdidion]

Also see #484

[DavyCats]

Changing from runtime to requirements would constitute a breaking change, so this would have to be part of 2.0, right? Unless requirements gets added as a synonym in 1.2 while runtime remains available as well.

[jdidion]

Yes, sorry, should have added more details. runtime will be deprecated but still supported in 1.2. It will be removed in 2.0.

[patmagee]

@DavyCats as @jdidion mentioned, we are not going to be breaking the spec here but will introduce an explicit deprecation of the runtime block in favour of the requirements section.

They will co-exist up until the 2.0 release. requirements provide a stricter vocabulary hopefully helping with portability

[vsmalladi]

Im not sure this is necessary. This seems unnecessary to move from runtime to requirements what is the value we are getting by doing this?

[jdidion]

Originally, we had planned in WDL 2.0 to change the semantics of runtime (in a breaking way) to only allow specific attributes. All optional attributes were to move to hints.

We then decided to implement this change in WDL 1.2, but since we cannot introduce a breaking change, we decided instead to deprecate runtime in favor of requirements and hints. The name requirements is also more clear than runtime regarding the intent of that section, and it also matches the term used in CWL.