feat(bigquery): update the api

#### bigquery:v2

The following keys were deleted:
- schemas.TrainingOptions.properties.preserveInputStructs.type (Total Keys: 1)

The following keys were added:
- schemas.ExternalDataConfiguration.properties.fileSetSpecType.type (Total Keys: 1)
- schemas.JobConfigurationLoad.properties.fileSetSpecType.type (Total Keys: 1)

Author: yoshi-automation