fix: change groth make target in readme (#357)

Co-authored-by: Mauro Toscano <12560266+MauroToscano@users.noreply.github.com>

Author: NicolasRampoldi

README.md

@@ -450,7 +450,7 @@ make batcher_send_sp1_task
 #### Send one Groth 16 proof
 
 ```bash
-make batcher_send_groth16_task
+make batcher_send_groth16_bn254_task
 ```
 
 #### Send infinite Groth 16 proofs