cli: add --cs.create_empty_blocks_interval flag (#4205)

Closes #4065

CHANGELOG_PENDING.md

@@ -92,6 +92,7 @@ program](https://hackerone.com/tendermint).
 - [types] \#2521 Add `NumTxs` to `BlockMeta` and `EventDataNewBlockHeader`
 - [docs] [\#4111](https://github.com/tendermint/tendermint/issues/4111) Replaced dead whitepaper link in README.md
 - [p2p] [\#4185](https://github.com/tendermint/tendermint/pull/4185) Simplify `SecretConnection` handshake with merlin
+- [cli] [\#4065](https://github.com/tendermint/tendermint/issues/4065) Add `--consensus.create_empty_blocks_interval` flag (@jgimeno)
 
 ### BUG FIXES:
 

cmd/tendermint/commands/run_node.go

@@ -59,6 +59,10 @@ func AddNodeFlags(cmd *cobra.Command) {
 		"consensus.create_empty_blocks",
 		config.Consensus.CreateEmptyBlocks,
 		"Set this to false to only produce blocks when there are txs or when the AppHash changes")
+	cmd.Flags().String(
+		"consensus.create_empty_blocks_interval",
+		string(config.Consensus.CreateEmptyBlocksInterval),
+		"The possible interval between empty blocks")
 }
 
 // NewRunNodeCmd returns the command that allows the CLI to start a node.