Always only return the last part of a branch

Not applying this causes certain environments (such as a local instance) to build artifacts in subdirectories with shortened names.

build.gradle

@@ -39,7 +39,8 @@ def getBranch(){
 	if (grgit == null) {
 		return "unknown"
 	}
-	return grgit.branch.current().name
+	def branch = grgit.branch.current().name
+	return branch.substring(branch.lastIndexOf("/") + 1)
 }
 
 allprojects {