Update references to set-output in GitHub workflows

[consideRatio]

From the GitHub post:

Starting 1st June 2023 workflows using save-state or set-output commands via stdout will fail with an error.

That means there is quite a bit of chore maintenance work needed to be done. Currently, I find 0 files referencing save-state and 10 files referencing set-output, and we can track it with this search.

Note that outputs are still usable etc, just how they are set has changed. The updates we should do are...

 - name: Set output
-  run: echo "::set-output name={name}::{value}"
+  run: echo "{name}={value}" >> $GITHUB_OUTPUT

And where setOutput() is used for javascript based actions, we should ensure v1.10.0 or higher version of @actions/core is used.

PRs opened to migrate

• ci: fix deprecation of set-output in github workflows zero-to-jupyterhub-k8s#2943
• Fix deprecation of set-output repo2docker-action#92
• ci: fix deprecation of set-output in github workflows mybinder.org-deploy#2413
  • ci: attempt to fix set-output again mybinder.org-deploy#2417
• Fix deprecation of set-output action-k3s-helm#79
• ci: fix deprecation of set-output in github workflows binderhub#1573
• ci: fix deprecation of set-output in github workflows the-littlest-jupyterhub#837

Challenges

• Sometimes we use Python instead of bash to write to the $GITHUB_OUTPUT file path. Then the equivalent pattern becomes...

  import os
  with open(os.environ["GITHUB_OUTPUT"], "a") as f:
      f.write(f"version={version}\n")

  • Relevant in ci: fix deprecation of set-output in github workflows zero-to-jupyterhub-k8s#2943
• Multiline strings evaluate differently when setting output into environment variables, and a strategy needs to be adopted like here to handle it.
  • Relevant in ci: fix deprecation of set-output in github workflows the-littlest-jupyterhub#837
• Environment variables can't be named like-this so a transition to like_this could be needed. But apparently, it isn't needed in this case, see @manics comment Fix deprecation of set-output action-k3s-helm#79 (comment).
  • Relevant in Fix deprecation of set-output action-k3s-helm#79
• A trick to escape new lines could not be used any more
  • Relevant in ci: attempt to fix set-output again mybinder.org-deploy#2417