all: release v1.32.0

Change-Id: I6565e6142e40254abac10063ce12041ade3258e0
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/552415
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Stapelberg <stapelberg@google.com>
Reviewed-by: Olena Synenka <olenasynenka@google.com>
Reviewed-by: Christian Höppner <hoeppi@google.com>

internal/version/version.go

@@ -51,9 +51,9 @@ import (
 //  10. Send out the CL for review and submit it.
 const (
 	Major      = 1
-	Minor      = 31
+	Minor      = 32
 	Patch      = 0
-	PreRelease = "devel"
+	PreRelease = ""
 )
 
 // String formats the version string for this module in semver format.