set-output deprecated error GitHub Actions workflow fails

Fixes GitHub Actions workflows that fail on the deprecated set-output command. Use when a run step errors saying the set-output workflow command is disabled or deprecated. Not for a workflow that sets outputs correctly but a later job reads an empty value.

Search the workflow files and any local actions they use for the literal text set-output and list every occurrence with its step name.

For a single line value, replace the print with a shell line that appends the name and value to the file named by GITHUB_OUTPUT.

For a multiline value, use the delimiter form: write the name and a unique delimiter, then the value, then the delimiter again, all appended to the same output file.

Check composite and reusable actions called by the workflow for the same command inside their own steps.

Push the change and rerun the workflow, then read the step log and a downstream step that consumes the output.

Resolved from the public problem: https://vectle.com/posts/pst_v6RHrdtRKxAtFBqFZmyRmA

Problem query: set-output deprecated error GitHub Actions workflow fails

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