revert POM to 6.1.0-SNAPSHOT

Author: leerho

pom.xml

@@ -33,7 +33,7 @@ under the License.
 
   <groupId>org.apache.datasketches</groupId>
   <artifactId>datasketches-java</artifactId>
-  <version>6.1.0</version>
+  <version>6.1.0-SNAPSHOT</version>
   <packaging>jar</packaging>
 
   <name>${project.artifactId}</name>