[nats-streaming] Release v0.4.0

Details can be found [here](https://github.com/nats-io/nats-streaming-server/releases/tag/v0.4.0)

library/nats-streaming

@@ -1,6 +1,6 @@
 Maintainers: Ivan Kozlovic <[email protected]> (@kozlovic)
 
-Tags: 0.3.8, latest
+Tags: 0.4.0, latest
 GitRepo: https://github.com/nats-io/nats-streaming-docker.git
-GitCommit: 8c51cccfe250cb144becd082e3ccdf531a31b30a
+GitCommit: 048c972a51fdacfe406cc254cfde35b8bcc0e1aa