feat(bigtableadmin): update the api

#### bigtableadmin:v2

The following keys were added:
- schemas.GoogleBigtableAdminV2TypeAggregate.properties.hllppUniqueCount.$ref (Total Keys: 1)
- schemas.GoogleBigtableAdminV2TypeAggregate.properties.max.$ref (Total Keys: 1)
- schemas.GoogleBigtableAdminV2TypeAggregate.properties.min.$ref (Total Keys: 1)
- schemas.GoogleBigtableAdminV2TypeAggregateHyperLogLogPlusPlusUniqueCount (Total Keys: 2)
- schemas.GoogleBigtableAdminV2TypeAggregateMax (Total Keys: 2)
- schemas.GoogleBigtableAdminV2TypeAggregateMin (Total Keys: 2)
- schemas.GoogleBigtableAdminV2TypeArray (Total Keys: 3)
- schemas.GoogleBigtableAdminV2TypeBool (Total Keys: 2)
- schemas.GoogleBigtableAdminV2TypeDate (Total Keys: 2)
- schemas.GoogleBigtableAdminV2TypeFloat32 (Total Keys: 2)
- schemas.GoogleBigtableAdminV2TypeFloat64 (Total Keys: 2)
- schemas.GoogleBigtableAdminV2TypeMap (Total Keys: 4)
- schemas.GoogleBigtableAdminV2TypeString (Total Keys: 8)
- schemas.GoogleBigtableAdminV2TypeStruct (Total Keys: 8)
- schemas.GoogleBigtableAdminV2TypeTimestamp (Total Keys: 2)
- schemas.Type.properties.arrayType.$ref (Total Keys: 1)
- schemas.Type.properties.boolType.$ref (Total Keys: 1)
- schemas.Type.properties.dateType.$ref (Total Keys: 1)
- schemas.Type.properties.float32Type.$ref (Total Keys: 1)
- schemas.Type.properties.float64Type.$ref (Total Keys: 1)
- schemas.Type.properties.mapType.$ref (Total Keys: 1)
- schemas.Type.properties.stringType.$ref (Total Keys: 1)
- schemas.Type.properties.structType.$ref (Total Keys: 1)
- schemas.Type.properties.timestampType.$ref (Total Keys: 1)

Author: yoshi-automation

docs/dyn/bigtableadmin_v2.projects.instances.clusters.backups.html

@@ -118,7 +118,7 @@ <h3>Method Details</h3>
   <pre>Copy a Cloud Bigtable backup to a new backup in the destination cluster located in the destination instance and project.
 
 Args:
-  parent: string, Required. The name of the destination cluster that will contain the backup copy. The cluster must already exists. Values are of the form: `projects/{project}/instances/{instance}/clusters/{cluster}`. (required)
+  parent: string, Required. The name of the destination cluster that will contain the backup copy. The cluster must already exist. Values are of the form: `projects/{project}/instances/{instance}/clusters/{cluster}`. (required)
   body: object, The request body.
     The object takes the form of: