Update sample.json

Author: jimmytwei

DirectProgramming/C++/Jupyter/OpenMP-offload-training/sample.json

@@ -17,6 +17,7 @@
           "intro/bin/prog1",
           "datatransfer/bin/prog2",
           "parallelism/bin/prog3",
+          "USM/bin/prog4",
           "make clean"
         ]
       }