chore: Update discovery artifacts (#1328)

## Deleted keys were detected in the following stable discovery artifacts:
admindirectoryv1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/1feda6f78f168e28d7842f49ad91fb00dc24ec19)
bigqueryreservationv1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/7e6c78d448e472caaa67971160fdd44ccce061b0)
computev1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/131a5cd5bda8512217aa461042b33fb287790839)
doubleclickbidmanagerv1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/d20e7e2553a1ea5d3690afba366683d4eb0ca647)
doubleclickbidmanagerv11[ [More details]](https://github.com/googleapis/google-api-python-client/commit/d20e7e2553a1ea5d3690afba366683d4eb0ca647)
serviceconsumermanagementv1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/864ef4795a0e89263859f493f9c40d1a85e90c28)
serviceusagev1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/ecd65a89c54132856b47747439faf901dbfbafcb)

## Deleted keys were detected in the following pre-stable discovery artifacts:
bigqueryreservationv1beta1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/7e6c78d448e472caaa67971160fdd44ccce061b0)
computealpha[ [More details]](https://github.com/googleapis/google-api-python-client/commit/131a5cd5bda8512217aa461042b33fb287790839)
computebeta[ [More details]](https://github.com/googleapis/google-api-python-client/commit/131a5cd5bda8512217aa461042b33fb287790839)
serviceconsumermanagementv1beta1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/864ef4795a0e89263859f493f9c40d1a85e90c28)
serviceusagev1beta1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/ecd65a89c54132856b47747439faf901dbfbafcb)

## Discovery Artifact Change Summary:
admindirectoryv1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/1feda6f78f168e28d7842f49ad91fb00dc24ec19)
bigqueryreservationv1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/7e6c78d448e472caaa67971160fdd44ccce061b0)
bigqueryreservationv1beta1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/7e6c78d448e472caaa67971160fdd44ccce061b0)
computealpha[ [More details]](https://github.com/googleapis/google-api-python-client/commit/131a5cd5bda8512217aa461042b33fb287790839)
computebeta[ [More details]](https://github.com/googleapis/google-api-python-client/commit/131a5cd5bda8512217aa461042b33fb287790839)
computev1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/131a5cd5bda8512217aa461042b33fb287790839)
containerv1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/9bc4a12e7ab57a1b5a5d3637087b80b3008e3352)
containerv1beta1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/9bc4a12e7ab57a1b5a5d3637087b80b3008e3352)
doubleclickbidmanagerv1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/d20e7e2553a1ea5d3690afba366683d4eb0ca647)
doubleclickbidmanagerv11[ [More details]](https://github.com/googleapis/google-api-python-client/commit/d20e7e2553a1ea5d3690afba366683d4eb0ca647)
serviceconsumermanagementv1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/864ef4795a0e89263859f493f9c40d1a85e90c28)
serviceconsumermanagementv1beta1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/864ef4795a0e89263859f493f9c40d1a85e90c28)
serviceusagev1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/ecd65a89c54132856b47747439faf901dbfbafcb)
serviceusagev1beta1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/ecd65a89c54132856b47747439faf901dbfbafcb)
diff --git a/googleapiclient/discovery_cache/documents/adexchangebuyer2.v2beta1.json b/googleapiclient/discovery_cache/documents/adexchangebuyer2.v2beta1.json
index f774e0b..8f7caf0 100644
--- a/googleapiclient/discovery_cache/documents/adexchangebuyer2.v2beta1.json
+++ b/googleapiclient/discovery_cache/documents/adexchangebuyer2.v2beta1.json
@@ -2500,7 +2500,7 @@
       }
     }
   },
-  "revision": "20210427",
+  "revision": "20210428",
   "rootUrl": "https://adexchangebuyer.googleapis.com/",
   "schemas": {
     "AbsoluteDateRange": {
@@ -5069,7 +5069,7 @@
       "type": "object"
     },
     "NonGuaranteedFixedPriceTerms": {
-      "description": "Terms for Preferred Deals. Note that Preferred Deals cannot be created via the API at this time, but can be returned in a get or list request.",
+      "description": "Terms for Preferred Deals.",
       "id": "NonGuaranteedFixedPriceTerms",
       "properties": {
         "fixedPrices": {
@@ -5249,7 +5249,7 @@
       "type": "object"
     },
     "Product": {
-      "description": "Note: this resource requires whitelisting for access. Please contact your account manager for access to Marketplace resources. A product is a segment of inventory that a seller wishes to sell. It is associated with certain terms and targeting information which helps the buyer know more about the inventory.",
+      "description": "A product is a segment of inventory that a seller wishes to sell. It is associated with certain terms and targeting information which helps the buyer know more about the inventory.",
       "id": "Product",
       "properties": {
         "availableEndTime": {
@@ -5341,7 +5341,7 @@
       "type": "object"
     },
     "Proposal": {
-      "description": "Note: this resource requires whitelisting for access. Please contact your account manager for access to Marketplace resources. Represents a proposal in the Marketplace. A proposal is the unit of negotiation between a seller and a buyer and contains deals which are served. Note: you can not update, create, or otherwise modify Private Auction or Preferred Deals deals through the API. Fields are updatable unless noted otherwise.",
+      "description": "Represents a proposal in the Marketplace. A proposal is the unit of negotiation between a seller and a buyer and contains deals which are served. Note: You can't update, create, or otherwise modify Private Auction deals through the API. Fields are updatable unless noted otherwise.",
       "id": "Proposal",
       "properties": {
         "billedBuyer": {
@@ -5487,7 +5487,7 @@
       "type": "object"
     },
     "PublisherProfile": {
-      "description": "Note: this resource requires whitelisting for access. Please contact your account manager for access to Marketplace resources. Represents a publisher profile (https://support.google.com/admanager/answer/6035806) in Marketplace. All fields are read only. All string fields are free-form text entered by the publisher unless noted otherwise.",
+      "description": "Represents a publisher profile (https://support.google.com/admanager/answer/6035806) in Marketplace. All fields are read only. All string fields are free-form text entered by the publisher unless noted otherwise.",
       "id": "PublisherProfile",
       "properties": {
         "audienceDescription": {