Update ipu_config.json

ipu_config.json

@@ -16,5 +16,5 @@
 
   "ipus_per_replica": 4,
   "layers_per_ipu": [3, 7, 7, 7],
-  "matmul_proportion": [0.1, 0.2, 0.25, 0.25],
+  "matmul_proportion": [0.1, 0.2, 0.25, 0.25]
 }