chore: release v0.32.0 (#664)

CHANGES.md

diff --git a/CHANGES.md b/CHANGES.md
index b87643c..4d1f3ee 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,13 @@
+# v0.32.0
+
+- option:
+  - Add experimental ImpersonateCredentials option for impersonating a service
+    account.
+- Various updates to autogenerated clients.
+
+_Please note:_ the release version is not indicative of an individual client's
+stability or version.
+
 # v0.31.0
 
 - cloudcommerceprocurement: