Release v1.3.0-beta.2: Decrease default tx pool size from 4096 to 204…

…8. (#1483)

This was included in v1.2.5, but missed when preparing to release v1.3.0-beta.2.  So this commits adds it, and this is what will be used for the v1.3.0-beta.2 release.

core/tx_pool.go

@@ -196,7 +196,7 @@ var DefaultTxPoolConfig = TxPoolConfig{
 	PriceBump:  10,
 
 	AccountSlots: 16,
-	GlobalSlots:  4096,
+	GlobalSlots:  2048,
 	AccountQueue: 64,
 	GlobalQueue:  1024,