ci: label pull requests based on their target branch

[Lehoczky]

🔗 Linked issue

❓ Type of change

• 📖 Documentation (updates to the documentation, readme or JSdoc annotations)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

I've seen Daniel adding the 2.x and 3.x labels manually to PRs and wanted to help him out by labelling my own PR. Unfortunately, contributors don't have permission to edit PR labels, so I couldn't do that.

This PR makes this process automated.

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

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[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

❗ No coverage uploaded for pull request base (main@0eb9caf). Click here to learn what that means.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #24468   +/-   ##
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  Coverage        ?   58.65%           
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  Files           ?        5           
  Lines           ?      861           
  Branches        ?       46           
=======================================
  Hits            ?      505           
  Misses          ?      356           
  Partials        ?        0           

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[Lehoczky]

Looks like the GITHUB_TOKEN is missing some permissions. I'm not sure what is needed to add a label to a PR, but pull_request: write should be enough intuitively.

[danielroe]

This is a great idea. ❤️

It might be that the token on your fork doesn't have permissions to add labels on the main branch, or otherwise anyone could end up doing nefarious things.

I would suggest instead using the pull_request_target event which can run when the pull request is first opened, e.g.:

nuxt/.github/workflows/semantic-pull-requests.yml

Lines 3 to 8 in 9ef94d6

	on:
	pull_request_target:
	types:
	- opened
	- edited
	- synchronize

This will also run 'from' the main branch so shouldn't have any permission issues.

[Lehoczky]

Oh silly me, I haven't realized the token being used is from my fork 😅

I've updated the trigger as you suggested, thank you for the feedback!^^ This means though that the workflow won't run for this PR, but I've tested the exact same code in one of my own repositories to make sure it works.