Set outputs is currently using syntax which is due to be deprecated

[TomMGWhit]

The actions output method is currently using Syntax that will be deprecated on 31/05/23. Will this be updated in line with the guidance issued by GitHub?

actions method using deprecated syntax: https://github.com/fastai/ghapi/blob/master/ghapi/actions.py#L119

guidance issued by GitHub: https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

Currently, using the method results in the following warning being generated on workflows:
The set-output command is deprecated and will be disabled soon. Please upgrade to using Environment Files. For more information see: https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/Show more