fix backport typo

Author: jdar

hapi-fhir-docs/src/main/resources/ca/uhn/hapi/fhir/changelog/8_8_0/7536-Codesystem-loading-in-DBPM.yaml

@@ -1,5 +1,5 @@
 ---
 type: fix
 issue: 7536
-backport: 6.8.5
+backport: 8.6.5
 title: "When running in Database Partition mode (see PartitionSettings#isDatabasePartitionMode), Code System expansion would fail with a duplicate column error. This has been corrected."