ci(linter): add workflow permissions (#24)

## 💌 Description

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## 🔗 Related issue

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Fixes: #

## 🏗️ Type of change

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- [ ] 📚 Examples/docs/tutorials
- [ ] 🐛 Bug fix (non-breaking change which fixes an issue)
- [ ] 🥂 Improvement (non-breaking change which improves an existing
feature)
- [ ] 🚀 New feature (non-breaking change which adds functionality)
- [ ] 💥 Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] 🚨 Security fix
- [ ] ⬆️ Dependencies update

## ✅ Checklist

<!-- Mark with an `x` all the checkboxes that apply (like `[x]`) -->

- [ ] I've read the [`Code of
Conduct`](https://github.com/raven-actions/actionlint/blob/main/.github/CODE_OF_CONDUCT.md)
document.
- [ ] I've read the
[`Contributing`](https://github.com/raven-actions/actionlint/blob/main/.github/CONTRIBUTING.md)
guide.

.github/workflows/linter.yml

@@ -14,6 +14,10 @@ on: # yamllint disable-line rule:truthy
     branches:
       - main
 
+permissions:
+  contents: read
+  pull-requests: read
+
 jobs:
   linter:
     name: Linter