all: release v0.58.0

This change will be tagged v0.58.0.

Change-Id: I5a8616646142c5d1e6ed6b515ea53cd5bf9d8a1a
Reviewed-on: https://code-review.googlesource.com/c/gocloud/+/57270
Reviewed-by: Tyler Bui-Palsulich <tbp@google.com>
diff --git a/CHANGES.md b/CHANGES.md
index bd56fc4..5868db4 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,5 +1,32 @@
 # Changes
 
+## v0.58.0
+
+### Deprecation notice
+
+- `cloud.google.com/go/monitoring/apiv3` has been deprecated due to breaking
+  changes in the API. Please migrate to `cloud.google.com/go/monitoring/apiv3/v2`.
+
+### Changes
+
+- all:
+  - The remaining uses of gtransport.Dial have been removed.
+  - The `genproto` dependency has been updated to a version that makes use of
+    new `protoreflect` library. For more information on these protobuf changes
+    please see the following post from the official Go blog:
+    https://blog.golang.org/protobuf-apiv2.
+- internal:
+  - Started generation of datastore admin v1 client.
+  - Updated protofuf version used for generation to 3.12.X.
+  - Update the release levels for several APIs.
+  - Generate clients with protoc-gen-go@v1.4.1.
+- monitoring:
+  - Re-enable generation of monitoring/apiv3 under v2 directory (see deprecation
+    notice above).
+- profiler:
+  - Fixed flakiness in tests.
+- Various updates to autogenerated clients.
+
 ## v0.57.0
 
 - all: