Fix package team members list

Why is this change being made?

https://about.gitlab.com/handbook/engineering/development/ops/package/#team-members is listing wrong members.

A previous fix attempted to generate that list but the fix was not accurate: targeting @dcroft's role is pulling too many members 😺

This MR will add a role_regexp so that members not in the Package team will not be listed.

Here is the list in the deployed app from this MR: https://10io-fix-package-team-members.about.gitlab-review.app/handbook/engineering/development/ops/package/#team-members. No more guests to the list 😺

Author Checklist

• Provided a concise title for the MR
• Added a description to this MR explaining the reasons for the proposed change, per say-why-not-just-what
• Assign this change to the correct DRI
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