all: release v0.22.0

This commit will be tagged v0.22.0.

Change-Id: I3d1622adbcb3286f990f6d0926efd1650ae03607
Reviewed-on: https://code-review.googlesource.com/c/google-api-go-client/+/55110
Reviewed-by: Tyler Bui-Palsulich <tbp@google.com>

CHANGES.md

diff --git a/CHANGES.md b/CHANGES.md
index a12d102..36cc78b 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,22 @@
+# v0.22.0
+
+## Depreciation Notice
+
+- Package `google.golang.org/api/sql/v1beta4` has been deprecated as it was
+  generated under the wrong name. This package will be removed in a future
+  release. Please migrate to: `google.golang.org/api/sqladmin/v1beta4`.
+
+## Changes
+
+- Apigee client has temporarily been disabled.
+
+- Updated custom search example to be in line with new API.
+
+- Various updates to autogenerated clients.
+
+_Please note:_ the release version is not indicative of an individual client's
+stability or version.
+
 # v0.21.0
 
 - Disabled automatic switching to *.mtls.googleapis.com endpoints.