chore: Update discovery artifacts (#1333)

## Deleted keys were detected in the following pre-stable discovery artifacts:
gkehubv1alpha[ [More details]](https://github.com/googleapis/google-api-python-client/commit/dcd01664ac4b7e2bd428f3e42d9528c722a19a4e)
gkehubv1beta[ [More details]](https://github.com/googleapis/google-api-python-client/commit/dcd01664ac4b7e2bd428f3e42d9528c722a19a4e)

## Discovery Artifact Change Summary:
androidenterprisev1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/362d0dd463193791b3ae981b35771e2c036ae337)
androidpublisherv3[ [More details]](https://github.com/googleapis/google-api-python-client/commit/90851f695283e9e741c5df2116228f3740cee32a)
artifactregistryv1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/e77297852bb1805dfc7746332844679c42b89794)
chromepolicyv1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/cd1df57c922c4300859db216157caf3eddacbf66)
dialogflowv3beta1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/bd668e18902364e0de1bca6474bc4dd29b7c347f)
filev1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/804ea3bc15b7f133597a1b3c1f24e0c9c5235b54)
gkehubv1alpha[ [More details]](https://github.com/googleapis/google-api-python-client/commit/dcd01664ac4b7e2bd428f3e42d9528c722a19a4e)
gkehubv1beta[ [More details]](https://github.com/googleapis/google-api-python-client/commit/dcd01664ac4b7e2bd428f3e42d9528c722a19a4e)
lifesciencesv2beta[ [More details]](https://github.com/googleapis/google-api-python-client/commit/a1b8cf21e766625fae5f10c37f6430d20cb0f362)
servicedirectoryv1beta1[ [More details]](https://github.com/googleapis/google-api-python-client/commit/b79051d8dc99227aa1ee4749e280b90d7ce7f959)

chore(acceleratedmobilepageurl): update the api
chore(adexchangebuyer): update the api
chore(adexchangebuyer2): update the api
chore(admob): update the api
chore(adsense): update the api
chore(analyticsadmin): update the api
chore(analyticsdata): update the api
chore(analyticsreporting): update the api
feat(androidenterprise): update the api
feat(androidpublisher): update the api
chore(apigateway): update the api
chore(apikeys): update the api
chore(area120tables): update the api
feat(artifactregistry): update the api
chore(bigquery): update the api
chore(blogger): update the api
chore(books): update the api
chore(chat): update the api
chore(chromemanagement): update the api
feat(chromepolicy): update the api
chore(chromeuxreport): update the api
chore(classroom): update the api
chore(cloudasset): update the api
chore(cloudbuild): update the api
chore(cloudchannel): update the api
chore(cloudprofiler): update the api
chore(cloudsearch): update the api
chore(cloudtrace): update the api
chore(containeranalysis): update the api
chore(customsearch): update the api
feat(dialogflow): update the api
chore(domainsrdap): update the api
chore(doubleclicksearch): update the api
chore(driveactivity): update the api
chore(essentialcontacts): update the api
chore(eventarc): update the api
chore(factchecktools): update the api
feat(file): update the api
chore(firebase): update the api
chore(firebasedatabase): update the api
chore(firebaseml): update the api
chore(fitness): update the api
feat(gkehub): update the api
chore(gmailpostmastertools): update the api
chore(iam): update the api
chore(iamcredentials): update the api
chore(language): update the api
chore(libraryagent): update the api
feat(lifesciences): update the api
chore(logging): update the api
chore(ml): update the api
chore(monitoring): update the api
chore(mybusinessaccountmanagement): update the api
chore(mybusinesslodging): update the api
chore(mybusinessplaceactions): update the api
chore(networkconnectivity): update the api
chore(orgpolicy): update the api
chore(osconfig): update the api
chore(pagespeedonline): update the api
chore(paymentsresellersubscription): update the api
chore(people): update the api
chore(playablelocations): update the api
chore(playcustomapp): update the api
chore(poly): update the api
chore(prod_tt_sasportal): update the api
chore(pubsublite): update the api
chore(realtimebidding): update the api
chore(recommender): update the api
chore(remotebuildexecution): update the api
chore(safebrowsing): update the api
chore(sasportal): update the api
chore(searchconsole): update the api
chore(serviceconsumermanagement): update the api
feat(servicedirectory): update the api
chore(serviceusage): update the api
chore(sheets): update the api
chore(smartdevicemanagement): update the api
chore(storage): update the api
chore(storagetransfer): update the api
chore(streetviewpublish): update the api
chore(sts): update the api
chore(tagmanager): update the api
chore(toolresults): update the api
chore(tpu): update the api
chore(vectortile): update the api
chore(videointelligence): update the api
chore(workflows): update the api
chore(youtube): update the api
chore(youtubeAnalytics): update the api
chore(youtubereporting): update the api
chore(docs): Add new discovery artifacts and reference documents
diff --git a/googleapiclient/discovery_cache/documents/paymentsresellersubscription.v1.json b/googleapiclient/discovery_cache/documents/paymentsresellersubscription.v1.json
index bdf1f30..ab3c608 100644
--- a/googleapiclient/discovery_cache/documents/paymentsresellersubscription.v1.json
+++ b/googleapiclient/discovery_cache/documents/paymentsresellersubscription.v1.json
@@ -337,7 +337,7 @@
               }
             },
             "undoCancel": {
-              "description": "Used by partners to revoke the pending cancellation of a subscription, which is currently in `STATE_WAITING_TO_CANCEL` state. If the subscription is already cancelled, the request will fail. It should be called directly by the partner using service accounts.",
+              "description": "Used by partners to revoke the pending cancellation of a subscription, which is currently in `STATE_CANCEL_AT_END_OF_CYCLE` state. If the subscription is already cancelled, the request will fail. It should be called directly by the partner using service accounts.",
               "flatPath": "v1/partners/{partnersId}/subscriptions/{subscriptionsId}:undoCancel",
               "httpMethod": "POST",
               "id": "paymentsresellersubscription.partners.subscriptions.undoCancel",
@@ -366,7 +366,7 @@
       }
     }
   },
-  "revision": "20210428",
+  "revision": "20210501",
   "rootUrl": "https://paymentsresellersubscription.googleapis.com/",
   "schemas": {
     "GoogleCloudPaymentsResellerSubscriptionV1CancelSubscriptionRequest": {