SSO doc update (logout).

GigyaSwift/README.md

@@ -477,6 +477,11 @@ gigya.sso(viewController: self, params: [“rp_context”: [“context_key”: 
     }	
 ```
 
+**Note:**
+When using mobile SSO (single sign-on using the central login page), logging out using the SDK's logout method will only log the user out of the current API key used.
+The user will not be logged out of the other group sites.
+
+
 ## FIDO/WebAuthn Authentication
 FIDO is a passwordless authentication method that enables password-only logins to be replaced with secure and fast login experiences across websites and apps.
 Our SDK provides an interface to register a passkey, login, and revoke passkeys created using Fido/Passkeys, backed by our WebAuthn service.