chore(networkmanagement): update the api

Author: yoshi-automation

googleapiclient/discovery_cache/documents/networkmanagement.v1.json

@@ -591,7 +591,7 @@
       }
     }
   },
-  "revision": "20210624",
+  "revision": "20210721",
   "rootUrl": "https://networkmanagement.googleapis.com/",
   "schemas": {
     "AbortInfo": {
@@ -1625,7 +1625,8 @@
             "NEXT_HOP_VPN_GATEWAY",
             "NEXT_HOP_INTERNET_GATEWAY",
             "NEXT_HOP_BLACKHOLE",
-            "NEXT_HOP_ILB"
+            "NEXT_HOP_ILB",
+            "NEXT_HOP_ROUTER_APPLIANCE"
           ],
           "enumDescriptions": [
             "Unspecified type. Default value.",
@@ -1638,7 +1639,8 @@
             "Next hop is a VPN gateway. This scenario only happens when tracing connectivity from an on-premises network to Google Cloud through a VPN. The analysis simulates a packet departing from the on-premises network through a VPN tunnel and arriving at a Cloud VPN gateway.",
             "Next hop is an internet gateway.",
             "Next hop is blackhole; that is, the next hop either does not exist or is not running.",
-            "Next hop is the forwarding rule of an Internal Load Balancer."
+            "Next hop is the forwarding rule of an Internal Load Balancer.",
+            "Next hop is a [router appliance instance](https://cloud.google.com/network-connectivity/docs/network-connectivity-center/concepts/ra-overview)."
           ],
           "type": "string"
         },