[Release 0.5.2] Update latest version in README (#155)

Co-authored-by: onobc <onobc@apache.org>
diff --git a/README.adoc b/README.adoc
index 6c630e4..8cdc631 100644
--- a/README.adoc
+++ b/README.adoc
@@ -19,7 +19,7 @@
 = Reactive client for Apache Pulsar
 
 :github: https://github.com/apache/pulsar-client-reactive
-:latest_version: 0.5.1
+:latest_version: 0.5.2
 
 Reactive client for Apache Pulsar which is compatible with the Reactive Streams specification.
 This uses Project Reactor as the Reactive Streams implementation.