all: release v0.54.0

This commit will be tagged v0.54.0.

Change-Id: I2b414c83f9582135aab3179f226b403af4b2cd27
Reviewed-on: https://code-review.googlesource.com/c/gocloud/+/52912
Reviewed-by: Noah Dietz <ndietz@google.com>
diff --git a/CHANGES.md b/CHANGES.md
index 744d1a2..3fa4900 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,5 +1,17 @@
 # Changes
 
+## v0.54.0
+
+- all:
+  - remove unused golang.org/x/exp from mod file
+  - update godoc.org links to pkg.go.dev
+- compute/metadata:
+  - use defaultClient when http.Client is nil
+  - remove subscribeClient
+- iam:
+  - add support for v3 policy and IAM conditions
+- Various updates to autogenerated clients.
+
 ## v0.53.0
 
 - all: most clients now use transport/grpc.DialPool rather than Dial (see #1777 for outliers).