The following Dataflow templates now support user-defined functions (UDFs) written in Python

## Feature The following Dataflow templates now support user-defined functions (UDFs) written in Python: * [Cloud Storage Text to BigQuery](https://cloud.google.com/dataflow/docs/guides/templates/provided/cloud-storage-to-bigquery-python-udf) * [Cloud Storage Text to BigQuery (Stream)](https://cloud.google.com/dataflow/docs/guides/templates/provided/text-to-bigquery-stream-python-udf) * [Pub/Sub to BigQuery](https://cloud.google.com/dataflow/docs/guides/templates/provided/pubsub-to-bigquery-python-udf) * [Pub/Sub Proto to BigQuery](https://cloud.google.com/dataflow/docs/guides/templates/provided/pubsub-proto-to-bigquery-python-udf)