pubsub: release pubsub/v1.4.0

This PR will be tagged pubsub/v1.4.0

Change-Id: Ie5cbef9818b1d409bcb144dd5d706b5c89396c51
Reviewed-on: https://code-review.googlesource.com/c/gocloud/+/56970
Reviewed-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Cody Oss <codyoss@google.com>
diff --git a/internal/version/version.go b/internal/version/version.go
index 4ee1054..a31e75c 100644
--- a/internal/version/version.go
+++ b/internal/version/version.go
@@ -26,7 +26,7 @@
 
 // Repo is the current version of the client libraries in this
 // repo. It should be a date in YYYYMMDD format.
-const Repo = "20200526"
+const Repo = "20200528"
 
 // Go returns the Go runtime version. The returned string
 // has no whitespace.
diff --git a/pubsub/CHANGES.md b/pubsub/CHANGES.md
index 49de654..2217f2c 100644
--- a/pubsub/CHANGES.md
+++ b/pubsub/CHANGES.md
@@ -1,5 +1,9 @@
 # Changes
 
+## v1.4.0
+
+- Add support for upcoming ordering keys feature.
+
 ## v1.3.1
 
 - Fix bug with removing dead letter policy from a subscription