chore: Set permissions for GitHub actions

Restrict the GitHub token permissions only to the required ones; this
way, even if the attackers will succeed in compromising your workflow,
they won’t be able to do much.

Included permissions for the action. https://github.com/ossf/scorecard/blob/main/docs/checks.md#token-permissions
https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#permissions

https://docs.github.com/en/actions/using-jobs/assigning-permissions-to-jobs

Keeping your GitHub Actions and workflows secure Part 1: Preventing pwn requests

.github/workflows/main.yml

@@ -8,6 +8,9 @@ on:
         branches:
             - "**"
 
+permissions:
+  contents: read
+
 jobs:
     prettier:
         runs-on: ubuntu-latest