Workflows: Component CHAGELOG update check fails on PR from forked repository

[t-hamano]

Description

Tested on #49816

A workflow has been introduced in #49443 to check for updates to the CHANGELOG file of component packages. This workflow does not appear to work for PRs submitted from forked repositories.

Step-by-step reproduction instructions

The complete procedure I followed is as follows:

• Clone the Gutenberg repository on GitHub
• Run git clone https://github.com/{my-username}/gutenberg.git
• Make changes to the .js file in the components package
• Commit, push, and submit a PR
• Confirm @wordpress/components CHANGELOG update runs
• Workflow fails (expected)
• Make changes to the /packages/components/CHANGELOG.md file
• Commit and push
• Confirm @wordpress/components CHANGELOG update runs
• Workflow fails (not expected)

[t-hamano]

It might be necessary to rewrite part of the GitHub Action, like this PR

fix: ce spec action for PRs from forks by vishnu-narayanan · Pull Request #4587 · chatwoot/chatwoot

[chad1008]

Thanks for testing and troubleshooting @t-hamano, that does indeed look like exactly what we needed. I've made the necessary change in #49906 and it's testing well for me from a forked repo!