assign to slice rather than append

Signed-off-by: Joni Collinge <jonathancollinge@live.com>

internal/component/azure/servicebus/subscription.go

@@ -363,8 +363,10 @@ func (s *Subscription) RenewLocksBlocking(ctx context.Context, receiver Receiver
 				// Snapshot the messages to try to renew locks for.
 				s.mu.RLock()
 				msgs := make([]*azservicebus.ReceivedMessage, 0, len(s.activeMessages))
+				var i int
 				for _, m := range s.activeMessages {
-					msgs = append(msgs, m)
+					msgs[i] = m
+					i++
 				}
 				s.mu.RUnlock()