Return assets from driver invocation

[maddenp-noaa]

Synopsis

Currently, uwtools.api.execute.execute() returns a bool meant to indicate whether the task ran to completion. Instead, return the iotaa Assets that are yielded by the task, which allows a caller to extract references (via iotaa.refs()) to the assets the task made ready. For example, execute()ing a namelist driver task would now return a reference to the on-disk namelist file, which the caller could use for whatever purpose. See the updated unit tests for an example.

Type

• Documentation
• Enhancement (adds new functionality)

Impact

• This is a breaking change (changes existing functionality) but it's unlikely any user would notice

Checklist

• I have added myself and any co-authors to the PR's Assignees list.
• I have reviewed the documentation and have made any updates necessitated by this change.