Update taxonomy.json

taxonomy.json

@@ -148,14 +148,10 @@
     ]
     },
     {
-        "name": "Adversarial Robustness",
+        "name": "Adversarial Attacks and Robustness",
         "children": [
-         {"name": "Adversarial Attacks",
-         "children": [
-             {"name": "Backdoor Attacks"}
-             ]
-         }
-        ]
+         {"name": "Backdoor Attacks"}
+         ]
     },
     {
         "name": "Biases in NLP",