chore: release bigtable 1.7.0 (googleapis#3435)

chore: release spanner 1.13.0 (googleapis#3423)

Co-authored-by: Thiago Nunes <[email protected]>

chore: release datastore 1.4.0 (googleapis#3421)

chore: release bigquery 1.15.0 (googleapis#3427)

🤖 I have created a release \*beep\* \*boop\* 
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## [1.15.0](https://www.github.com/googleapis/google-cloud-go/compare/bigquery/v1.14.0...v1.15.0) (2021-01-14)


### Features

* **bigquery:** add reservation usage stats to query statistics ([googleapis#3403](https://www.github.com/googleapis/google-cloud-go/issues/3403)) ([112bcde](https://www.github.com/googleapis/google-cloud-go/commit/112bcdeb7cee1b44f337d3e5398a0d0820e93162))
* **bigquery:** add support for allowing Javascript UDFs to indicate determinism ([googleapis#3534](https://www.github.com/googleapis/google-cloud-go/issues/3534)) ([2f417a3](https://www.github.com/googleapis/google-cloud-go/commit/2f417a39d93402fbb1e5e3001645019782d7d656)), refs [googleapis#3533](https://www.github.com/googleapis/google-cloud-go/issues/3533)


### Bug Fixes

* **bigquery:** address possible panic due to offset checking in handleInsertErrors  ([googleapis#3524](https://www.github.com/googleapis/google-cloud-go/issues/3524)) ([5288511](https://www.github.com/googleapis/google-cloud-go/commit/52885115af3e95cdfd1ec784837fb1df7fe01446)), refs [googleapis#3519](https://www.github.com/googleapis/google-cloud-go/issues/3519)

This PR was generated with [Release Please](https://github.com/googleapis/release-please). See [documentation](https://github.com/googleapis/release-please#release-please).

chore: release 0.75.0 (googleapis#3453)

chore: release pubsublite 0.5.0 (googleapis#3483)

chore: release 0.74.0 (googleapis#3404)

chore: release pubsub 1.9.1 (googleapis#3426)

chore: release pubsublite 0.4.0 (googleapis#3412)

* chore: release pubsublite 0.4.0

chore: release 0.73.0 (googleapis#3194)