chore: bump to 500 keys

Author: alexghr

spartan/environments/testnet-v4.env

@@ -74,7 +74,7 @@ SEQ_MAX_TX_PER_CHECKPOINT=72
 
 
 VALIDATOR_REPLICAS=1
-VALIDATORS_PER_NODE=96
+VALIDATORS_PER_NODE=500
 VALIDATOR_PUBLISHERS_PER_REPLICA=4
 VALIDATOR_PUBLISHER_MNEMONIC_START_INDEX=5000
 VALIDATOR_RESOURCE_PROFILE="prod"