Set SNAPSHOT version to make release script happy

Author: oschwald

pom.xml

@@ -3,7 +3,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>com.maxmind.geoip2</groupId>
     <artifactId>geoip2</artifactId>
-    <version>2.16.1</version>
+    <version>2.16.1-SNAPSHOT</version>
     <packaging>jar</packaging>
     <name>MaxMind GeoIP2 API</name>
     <description>GeoIP2 webservice client and database reader</description>