Update RELEASE_NOTES

Author: bourtemb

RELEASE_NOTES

@@ -2,6 +2,10 @@
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 1. Add Tango::string_free and fix memory leak in zmq_event_subscription_change() (#457,#460)
 2. Fix bug impacting device servers using dynamic attributes (#458,#459)
+3. Fix reconnection issues when a client subscribes to several events (#455)
+4. Fix some event compatibility issues with device server <= Tango 8 (#456)
+5. Fix event field in EventData structure passed to user's callback (broken in Tango 9.3.0 and 9.3.1)
+6. Fix attribute name in EventData structure passed to user's callback for Attribute Config events
 
 9.3.1
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