fix invalid dimensions of MLM inputs/outputs example

Author: fmigneault

examples/item_bands_expression.json

@@ -86,7 +86,7 @@
         "input": {
           "shape": [
             -1,
-            13,
+            4,
             64,
             64
           ],
@@ -110,7 +110,7 @@
         "result": {
           "shape": [
             -1,
-            10
+            2
           ],
           "dim_order": [
             "batch",