all: release v0.57.0

This commit will be tagged v0.57.0.

Change-Id: Ie8cd607757d2ddfc84f2ef7e8f48a527a2dfa868
Reviewed-on: https://code-review.googlesource.com/c/gocloud/+/55810
Reviewed-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Tyler Bui-Palsulich <tbp@google.com>
diff --git a/CHANGES.md b/CHANGES.md
index 52e67d6..bd56fc4 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,5 +1,26 @@
 # Changes
 
+## v0.57.0
+
+- all:
+  - Update module dependency `google.golang.org/api` to `v0.21.0`.
+- errorreporting:
+  - Add exported SetGoogleClientInfo wrappers to manual file.
+- expr/v1alpha1:
+  - Deprecate client. This client will be removed in a future release.
+- internal:
+  - Fix possible data race in TestTracer.
+  - Pin versions of tools used for generation.
+  - Correct the release levels for BigQuery APIs.
+  - Start generation osconfig v1.
+- longrunning:
+  - Add exported SetGoogleClientInfo wrappers to manual file.
+- monitoring:
+  - Stop generation of monitoring/apiv3 because of incoming breaking change.
+- trace:
+  - Add exported SetGoogleClientInfo wrappers to manual file.
+- Various updates to autogenerated clients.
+
 ## v0.56.0
 
 - secretmanager: