Add release note for RSA CA changes

Signed-off-by: Matthew Sykes <sykesmat@us.ibm.com>

release_notes/v2.2.2.md

@@ -20,6 +20,15 @@ MSP configuration. This fix resolves this by validating new consenter certs
 against the simulated config to ensure it factors in any simultaneous
 config updates.
 
+**FAB-18308: Restore support for MSPs that contain RSA certificate authorities**
+
+While Fabric has never supported RSA for transaction signatures or validation,
+certificate authorities included in MSP definitions could be associated with
+RSA keys. This ability was inadvertently removed during the development of
+release 2.0 and prevented migration of some networks to a 2.x version. With
+these changes, version 2.x components will no longer panic when attempting to
+initialize MSPs that include CA certificates associated with RSA keys.
+
 Deprecations (existing)
 -----------------------