release(1.2.0-RC2): update changelog

CHANGELOG.md

@@ -2,6 +2,22 @@
 
 New features, fixed bugs, known defects and other noteworthy changes to each release of the Catena-X IAM - Keycloak instances.
 
+## 1.2.0-RC2
+
+### Change
+
+* added post-upgrade documentation for v1.2.0, see [Post-Upgrade Configuration](./charts/centralidp/README.md#post-upgrade-configuration)
+* added second license
+* changed license notice for images
+
+### Feature
+
+* added seeding job to upgrade the configuration of the CX-Central realm
+
+### Bugfix
+
+* updated CX-Central realm config with findings discovered during e2e testing
+
 ## 1.2.0-RC1
 
 ### Change