adjust permission for PR comments

[tonyhoo]

Description

Adjust permission for PR comments for pull_request_event

Related Issue

N/A

Type of Change

• Bug fix
• New feature
• Documentation update
• Performance improvement
• Code refactoring
• Other (please specify)

Checklist

• I have read the CONTRIBUTING document
• My code follows the project's coding style
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have updated the documentation accordingly
• [ x] I have added appropriate comments to my code, particularly in hard-to-understand areas

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[cheungdaven]

LGTM