find-inactive-members.rb - PR approval activity

When running find-inactive-members.rb, Pull Request approval is not taken into account for active user action. Therefore, user is marked as inactive. It seems only opening or commenting a Pull Request is taken as a user action.

Start with find-inactive-members.rb and trace how user activity is determined for pull requests. Reproduce the case with a user who only approves a pull request, then verify that this activity prevents the user from being marked inactive. No test file or additional entry point is mentioned in the issue.

由索引模型根據 Issue 內容生成。