Fix unit tests failing from headers missing, due to an update in bigq… (#551)
Fix unit tests failing from headers missing, due to an update in bigq… (#551)

* Fix unit tests failing from headers missing, due to an update in bigquery python library (https://github.com/googleapis/google-cloud-python/pull/7849/files#diff-340196d499e9d0eea25cd457f53bfa42L61).

Kaggle/docker-python,Kaggle/docker-python