Notify maintainers when bug referenced in code has changed status
### Problem to solve
In GNOME (and I suspect elsewhere) when working around issues we'll leave a comment with a link to the corresponding bug. It would be excellent if the maintainers of a project could get a pingback when the referenced bug has changed.
Obviously this is easier when the bugs are within the same gitlab realm, and that is likely the extent for which I would need this feature. Although, I could definitely see a value to being able to reference freedesktop.org's gitlab from GNOME's gitlab.
### Intended users
* [Delaney (Development Team Lead)](https://about.gitlab.com/handbook/marketing/product-marketing/roles-personas/#delaney-development-team-lead)
* [Sasha (Software Developer)](https://about.gitlab.com/handbook/marketing/product-marketing/roles-personas/#sasha-software-developer)
* [Sam (Security Analyst)](https://about.gitlab.com/handbook/marketing/product-marketing/roles-personas/#sam-security-analyst)
### Further details
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### Proposal
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### Permissions and Security
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### Documentation
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### Testing
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### What does success look like, and how can we measure that?
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### Links / references
issue