Update README to reference 'Data Management System' (#1087)

## PR Type
- [ ] Feature
- [ ] Hotfix
- [ ] Release
- [x] Documentation

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## Checklist
- [x] Code builds locally
- [x] Tests added or updated
- [x] CI is green
- [ ] Peer review completed

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### UAT
- [ ] Required → completed
- [x] Not required (explain below)
No functional change made.

Author: carlsixsmith-moj

README.md

@@ -20,7 +20,7 @@ HMPPS Creating Future Opportunities (CFO) utilise the Case Assessment and Tracki
 
 # Mechanism (How does it communicate with other systems? Frequency of data pull/push, reporting, events etc) 
 
-CATS relies on the external data from Nomis and Delius. This is aggregated and managed by the [CFO External Data Integration System](https://github.com/ministryofjustice/CFO-ExternalDataIntegrationSystem).
+CATS relies on the external data from Nomis and Delius. This is aggregated and managed by the [CFO Data Management System](https://github.com/ministryofjustice/CFO-DataManagementSystem).
 
 
 # Technology (What's the technology that drives the product? i.e. Azure, java script etc)