chore(transcoder): update the api

#### transcoder:v1beta1

The following keys were added:
- schemas.Job.properties.ttlAfterCompletionDays (Total Keys: 2)
- schemas.OperationMetadata (Total Keys: 11)
- schemas.Pad (Total Keys: 10)
- schemas.PreprocessingConfig.properties.pad (Total Keys: 1)
- schemas.SpriteSheet.properties.quality (Total Keys: 2)

Author: yoshi-automation