Update param_CH4_deepmd-kit-2.0.1.json (#694)

old keyword "stop_batch" -> new keyword "numb_steps"

Author: LiangWenshuo1118

examples/run/dp2.x-lammps-vasp/param_CH4_deepmd-kit-2.0.1.json

@@ -70,7 +70,7 @@
         },
         "training": {
             "set_prefix": "set",
-            "stop_batch": 2000,
+            "numb_steps": 2000,
             "batch_size": 1,
             "disp_file": "lcurve.out",
             "disp_freq": 1000,