chore: release bigquery 1.21.0 (#4614)

Co-authored-by: shollyman <shollyman@google.com>

bigquery/CHANGES.md

@@ -1,5 +1,20 @@
 # Changes
 
+## [1.21.0](https://www.github.com/googleapis/google-cloud-go/compare/bigquery/v1.20.1...bigquery/v1.21.0) (2021-08-16)
+
+
+### Features
+
+* **bigquery/storage/managedwriter:** add project autodetection ([#4605](https://www.github.com/googleapis/google-cloud-go/issues/4605)) ([d8cc9be](https://www.github.com/googleapis/google-cloud-go/commit/d8cc9be6f0314f585f708638834abfc209799724))
+* **bigquery/storage/managedwriter:** improve protobuf support ([#4589](https://www.github.com/googleapis/google-cloud-go/issues/4589)) ([a455082](https://www.github.com/googleapis/google-cloud-go/commit/a45508272a730e0ad81021695d2d8564e7c81631))
+* **bigquery/storage/managedwriter:** more instrumentation support ([#4601](https://www.github.com/googleapis/google-cloud-go/issues/4601)) ([ff488c8](https://www.github.com/googleapis/google-cloud-go/commit/ff488c86b9c1a1f02397bb579905fa049e59ac05))
+* **bigquery:** switch to centralized project autodetect logic ([#4625](https://www.github.com/googleapis/google-cloud-go/issues/4625)) ([18ff070](https://www.github.com/googleapis/google-cloud-go/commit/18ff070b8baa3ed7d324ca9ea00dcd66d7742340))
+
+
+### Bug Fixes
+
+* **bigquery/storage/managedwriter:** support non-default regions ([#4566](https://www.github.com/googleapis/google-cloud-go/issues/4566)) ([68418f9](https://www.github.com/googleapis/google-cloud-go/commit/68418f9e340def179eb5556aea433c0d07000b79))
+
 ### [1.20.1](https://www.github.com/googleapis/google-cloud-go/compare/bigquery/v1.20.0...bigquery/v1.20.1) (2021-08-06)