Set on-release.yml to trigger on release publishing instead of push

[hanleyyin]

Issue # (if applicable)

N/A

Reason for this change

Previously, this workflow triggered on a push with any tag. This was causing a weird edge case where workflows that were triggered on a forked branch of the repository with a release cut to it would show up on the parent repo.

If we change this workflow to trigger instead on the actual publishing of a release, this behavior should stop.

Description of changes

The workflow only triggers when a release is published, instead of when a push with a tag happens.

https://docs.github.com/en/webhooks/webhook-events-and-payloads?actionType=published#release

Describe any new or updated permissions being added

N/A

Description of how you validated changes

Tested by:

• Creating a fork of https://github.com/ARichman555 here: https://github.com/hanleyyin/ratchat
  • This is because I can't create a fork of my own repos
• Then, I made an Action to trigger on publish as well: https://github.com/hanleyyin/ratchat/blob/main/.github/workflows/on-release.yml, and cut a release on my fork.
  • Saw the corresponding Action in my fork
• Made a PR to ensure the parent repo also had the same action
  • Confirmed that when the parent repo made a release (v0.0.1), the Action is visible from the parent repo.
• Made a secondary branch, cut a release to it (triggering an Action run on the fork), and made a PR
  • Confirmed that this run is not visible from the parent

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