Prepare next development version (#532)

Co-authored-by: Walter Dziemianczyk <wdziemia@dropbox.com>

Author: wdziemia

gradle.properties

@@ -1,6 +1,6 @@
 # POM
 GROUP = com.dropbox.core
-VERSION_NAME=6.1.0
+VERSION_NAME=6.2.0-SNAPSHOT
 
 POM_URL = https://github.com/dropbox/dropbox-sdk-java/
 POM_SCM_URL = https://github.com/dropbox/dropbox-sdk-java/