[Version] Prepare for new version 5.6.0 (#132)

Author: kittinunf

gradle.properties

@@ -10,5 +10,5 @@ artifactUrl=https://github.com/kittinunf/Result
 artifactScm=git@github.com:kittinunf/result.git
 artifactLicenseName=MIT License
 artifactLicenseUrl=http://www.opensource.org/licenses/mit-license.php
-artifactPublishVersion=5.5.0
+artifactPublishVersion=5.6.0
 artifactGroupId=com.github.kittinunf.result