The `set-output` command is deprecated and will be disabled soon. Please upgrade to using Environment Files.

[diimpp]

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

[jasongitmail]

It looks like updating @actions/core from 1.6 to 1.10 might solve this, because the method being called is the same, just the implementation in @actions/core changed to use the new recommended approach.