feat(servicenetworking): update the api

#### servicenetworking:v1

The following keys were added:
- schemas.PartialDeleteConnectionMetadata (Total Keys: 2)

#### servicenetworking:v1beta

The following keys were added:
- schemas.PartialDeleteConnectionMetadata (Total Keys: 2)

googleapiclient/discovery_cache/documents/servicenetworking.v1.json

diff --git a/googleapiclient/discovery_cache/documents/servicenetworking.v1.json b/googleapiclient/discovery_cache/documents/servicenetworking.v1.json
index 3943c2a..32c3d2f 100644
--- a/googleapiclient/discovery_cache/documents/servicenetworking.v1.json
+++ b/googleapiclient/discovery_cache/documents/servicenetworking.v1.json
@@ -860,7 +860,7 @@
       }
     }
   },
-  "revision": "20210517",
+  "revision": "20210519",
   "rootUrl": "https://servicenetworking.googleapis.com/",
   "schemas": {
     "AddDnsRecordSetMetadata": {
@@ -2538,6 +2538,12 @@
       },
       "type": "object"
     },
+    "PartialDeleteConnectionMetadata": {
+      "description": "Metadata provided through GetOperation request for the LRO generated by Partial Delete Connection API",
+      "id": "PartialDeleteConnectionMetadata",
+      "properties": {},
+      "type": "object"
+    },
     "PeeredDnsDomain": {
       "description": "DNS domain suffix for which requests originating in the producer VPC network are resolved in the associated consumer VPC network.",
       "id": "PeeredDnsDomain",

googleapiclient/discovery_cache/documents/servicenetworking.v1beta.json

diff --git a/googleapiclient/discovery_cache/documents/servicenetworking.v1beta.json b/googleapiclient/discovery_cache/documents/servicenetworking.v1beta.json
index c5e455c..5ab86e0 100644
--- a/googleapiclient/discovery_cache/documents/servicenetworking.v1beta.json
+++ b/googleapiclient/discovery_cache/documents/servicenetworking.v1beta.json
@@ -307,7 +307,7 @@
       }
     }
   },
-  "revision": "20210517",
+  "revision": "20210519",
   "rootUrl": "https://servicenetworking.googleapis.com/",
   "schemas": {
     "AddDnsRecordSetMetadata": {
@@ -1826,6 +1826,12 @@
       },
       "type": "object"
     },
+    "PartialDeleteConnectionMetadata": {
+      "description": "Metadata provided through GetOperation request for the LRO generated by Partial Delete Connection API",
+      "id": "PartialDeleteConnectionMetadata",
+      "properties": {},
+      "type": "object"
+    },
     "PeeredDnsDomain": {
       "description": "DNS domain suffix for which requests originating in the producer VPC network are resolved in the associated consumer VPC network.",
       "id": "PeeredDnsDomain",