feat(paymentsresellersubscription): update the api

#### paymentsresellersubscription:v1

The following keys were deleted:
- schemas.GoogleCloudPaymentsResellerSubscriptionV1Promotion.properties.freeTrialDuration.readOnly (Total Keys: 1)

Author: yoshi-automation

docs/dyn/paymentsresellersubscription_v1.partners.promotions.html

@@ -114,7 +114,7 @@ <h3>Method Details</h3>
         &quot;A String&quot;,
       ],
       &quot;endTime&quot;: &quot;A String&quot;, # Optional. Specifies the end time (exclusive) of the period that the promotion is available in. If unset, the promotion is available indefinitely.
-      &quot;freeTrialDuration&quot;: { # Describes the length of a period of a time. # Output only. Specifies the duration of the free trial of the subscription.
+      &quot;freeTrialDuration&quot;: { # Describes the length of a period of a time. # Optional. Specifies the duration of the free trial of the subscription when promotion_type is PROMOTION_TYPE_FREE_TRIAL
         &quot;count&quot;: 42, # number of duration units to be included.
         &quot;unit&quot;: &quot;A String&quot;, # The unit used for the duration
       },

googleapiclient/discovery_cache/documents/paymentsresellersubscription.v1.json

@@ -366,7 +366,7 @@
       }
     }
   },
-  "revision": "20210927",
+  "revision": "20211004",
   "rootUrl": "https://paymentsresellersubscription.googleapis.com/",
   "schemas": {
     "GoogleCloudPaymentsResellerSubscriptionV1CancelSubscriptionRequest": {
@@ -604,8 +604,7 @@
         },
         "freeTrialDuration": {
           "$ref": "GoogleCloudPaymentsResellerSubscriptionV1Duration",
-          "description": "Output only. Specifies the duration of the free trial of the subscription.",
-          "readOnly": true
+          "description": "Optional. Specifies the duration of the free trial of the subscription when promotion_type is PROMOTION_TYPE_FREE_TRIAL"
         },
         "name": {
           "description": "Output only. Response only. Resource name of the subscription promotion. It will have the format of \"partners/{partner_id}/promotion/{promotion_id}\"",