GDPR compliance by itself is largely a legal issue which has no place here (and likely anywhere else on SE). This would include questions of the type "I want to do X. Will this be enough to be GDPR compliant?".
However, the linked question is concerned with a technical problem (just motivated by GDPR) and I believe it could be topical here. That said, I could imagine that this could also be asked on SO if this would be part of a larger CRM environment.