[maven-release-plugin] prepare for next development iteration

Author: truthbk

pom.xml

@@ -5,7 +5,7 @@
   <artifactId>java-dogstatsd-client</artifactId>
   <packaging>jar</packaging>
   <name>java-dogstatsd-client</name>
-  <version>2.9.0</version>
+  <version>2.9.1-SNAPSHOT</version>
   <description>A tiny library allowing Java applications to communicate with DataDog statsd instances easily.</description>
   <url>https://github.com/DataDog/java-dogstatsd-client</url>