refactor: update googleapis dep (googleapis/google-cloud-cpp-bigquery#47)
refactor: update googleapis dep (googleapis/google-cloud-cpp-bigquery#47)

* refactor: update googleapis dep

This is the same googleapis dep used by `-cpp`, which will make it
easier to merge this code into `-cpp`. This version of googleapis also
includes its own BUILD file for C++ targets, so we can remove our own
build targets for the BigQuery protos.


googleapis/google-cloud-cpp,googleapis/google-cloud-cpp,googleapis/google-cloud-cpp,googleapis/google-cloud-cpp