feat(workstations): update the API

#### workstations:v1beta

The following keys were added:
- schemas.EphemeralDirectory.description
- schemas.EphemeralDirectory.id
- schemas.EphemeralDirectory.properties.gcePd.$ref
- schemas.EphemeralDirectory.properties.gcePd.description
- schemas.EphemeralDirectory.properties.mountPath.description
- schemas.EphemeralDirectory.properties.mountPath.type
- schemas.EphemeralDirectory.type
- schemas.GceInstance.properties.serviceAccountScopes.description
- schemas.GceInstance.properties.serviceAccountScopes.items.type
- schemas.GceInstance.properties.serviceAccountScopes.type
- schemas.GcePersistentDisk.description
- schemas.GcePersistentDisk.id
- schemas.GcePersistentDisk.properties.diskType.description
- schemas.GcePersistentDisk.properties.diskType.type
- schemas.GcePersistentDisk.properties.readOnly.description
- schemas.GcePersistentDisk.properties.readOnly.type
- schemas.GcePersistentDisk.properties.sourceImage.description
- schemas.GcePersistentDisk.properties.sourceImage.type
- schemas.GcePersistentDisk.properties.sourceSnapshot.description
- schemas.GcePersistentDisk.properties.sourceSnapshot.type
- schemas.GcePersistentDisk.type
- schemas.Workstation.properties.startTime.description
- schemas.Workstation.properties.startTime.format
- schemas.Workstation.properties.startTime.readOnly
- schemas.Workstation.properties.startTime.type
- schemas.WorkstationConfig.properties.ephemeralDirectories.description
- schemas.WorkstationConfig.properties.ephemeralDirectories.items.$ref
- schemas.WorkstationConfig.properties.ephemeralDirectories.type
- schemas.WorkstationConfig.properties.replicaZones.description
- schemas.WorkstationConfig.properties.replicaZones.items.type
- schemas.WorkstationConfig.properties.replicaZones.type