Update deprecated lightning call

examples/pysr_demo.ipynb

@@ -1206,7 +1206,9 @@
       },
       "outputs": [],
       "source": [
-        "trainer = pl.Trainer(max_steps=total_steps, gpus=1, benchmark=True)"
+        "trainer = pl.Trainer(\n",
+        "    max_steps=total_steps, accelerator=\"gpu\", devices=1, benchmark=True\n",
+        ")\n"
       ]
     },
     {