match variable name wording with cli and env var name options

Author: jaireddjawed

main.go

@@ -215,7 +215,7 @@ func main() {
 			"All errors are tried using an exponential backoff strategy. "+
 			"The value must be greater than zero. "+
 			"Also set from environment variable VSO_BACKOFF_MULTIPLIER.")
-	flag.DurationVar(&cleanupOrphanedShadowSecretInterval, "cleanup-orphaned-shadow-secrets-interval", 1*time.Hour,
+	flag.DurationVar(&cleanupOrphanedShadowSecretInterval, "cleanup-orphaned-shadow-secret-interval", 1*time.Hour,
 		"The time interval between each execution of the cleanup process for cached shadow secrets"+
 			"associated with a deleted HCPVaultSecretsApp. "+
 			"Also set from environment variable VSO_HVSA_CLEANUP_ORPHANED_SHADOW_SECRET_INTERVAL.")