ci(labels): reduce permissions

[thomasleplus]

Readiness checklist

Please check the boxes below to confirm that you have followed the
required guidelines for contributions:

• All commits are signed.
• The title for this pull request is the same as the first commit's message and it follows the conventional commits specification. See commit history for examples.
• If this pull request includes code changes, they were all properly tested. Automated tests were also included where possible.
• If applicable, this pull request includes the relevant documentation for this change.
• If this pull request is related to an existing issue, you can use the same description below but in any case include a link to the issue like Fixes #ISSUE_NUMBER. or Closes #ISSUE_NUMBER..

Description

Reduce workflow permissions.