chore: Update discovery artifacts (#1306)

## Deleted keys were detected in the following pre-stable discovery artifacts:
bigqueryreservationv1beta1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/6a8b3c6bd7aef8c84d5ba64410b29cabf056102b)

## Discovery Artifact Change Summary:
adexchangebuyer2v2beta1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/949754477e811a0b490a35e7e7313bbd22918d8a)
artifactregistryv1beta2[ [More details]](https://github.com/googleapis/google-api-python-client/commit/3811667db343c8e4ca5479b668a14b4bceddd981)
bigquerydatatransferv1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/f0071f5468eaa0320920fbee1489dbc2cb5e195f)
bigqueryreservationv1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/6a8b3c6bd7aef8c84d5ba64410b29cabf056102b)
bigqueryreservationv1beta1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/6a8b3c6bd7aef8c84d5ba64410b29cabf056102b)
bigtableadminv2[ [More details]](https://github.com/googleapis/google-api-python-client/commit/d1ce2408cf8bf7deaab38f7ecff96e9cb5d5a02d)
containerv1beta1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/60a23f0cafcca5473a829e8b11280733f76a8271)
displayvideov1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/559fa7cf4c7d300947bb556eb8c2830a751c7b11)
loggingv2[ [More details]](https://github.com/googleapis/google-api-python-client/commit/a3c1055968a4d9ac2448b0540bf4e2005be2958f)
serviceusagev1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/e2a86e92aa0ab7cce0b936a764ea5440b35a62e9)
serviceusagev1beta1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/e2a86e92aa0ab7cce0b936a764ea5440b35a62e9)
diff --git a/googleapiclient/discovery_cache/documents/adexchangebuyer2.v2beta1.json b/googleapiclient/discovery_cache/documents/adexchangebuyer2.v2beta1.json
index 3e5eed3..97b8c77 100644
--- a/googleapiclient/discovery_cache/documents/adexchangebuyer2.v2beta1.json
+++ b/googleapiclient/discovery_cache/documents/adexchangebuyer2.v2beta1.json
@@ -2500,7 +2500,7 @@
       }
     }
   },
-  "revision": "20210421",
+  "revision": "20210422",
   "rootUrl": "https://adexchangebuyer.googleapis.com/",
   "schemas": {
     "AbsoluteDateRange": {
@@ -4373,10 +4373,34 @@
           "format": "int64",
           "type": "string"
         },
+        "impressionCap": {
+          "description": "The lifetime impression cap for CPM sponsorship deals. The deal will stop serving when the cap is reached.",
+          "format": "int64",
+          "type": "string"
+        },
         "minimumDailyLooks": {
           "description": "Daily minimum looks for CPD deal types.",
           "format": "int64",
           "type": "string"
+        },
+        "percentShareOfVoice": {
+          "description": "For sponsorship deals, this is the percentage of the seller's eligible impressions that the deal will serve until the cap is reached.",
+          "format": "int64",
+          "type": "string"
+        },
+        "reservationType": {
+          "description": "The reservation type for a Programmatic Guaranteed deal. This indicates whether the number of impressions is fixed, or a percent of available impressions. If not specified, the default reservation type is STANDARD.",
+          "enum": [
+            "RESERVATION_TYPE_UNSPECIFIED",
+            "STANDARD",
+            "SPONSORSHIP"
+          ],
+          "enumDescriptions": [
+            "An unspecified reservation type.",
+            "Non-sponsorship deal.",
+            "Sponsorship deals don't have impression goal (guaranteed_looks) and they are served based on the flight dates. For CPM Sponsorship deals, impression_cap is the lifetime impression limit."
+          ],
+          "type": "string"
         }
       },
       "type": "object"