The Task.leftShift(Closure) method has been deprecated

src/android/build-extras.gradle

@@ -25,24 +25,26 @@ cdvPluginPostBuildExtras.add({
     def outAssetsDir = inAssetsDir
     def outFile = new File(outAssetsDir, "cdvasset.manifest")
 
-    def newTask = task("cdvCreateAssetManifest") << {
-        def contents = new HashMap()
-        def sizes = new HashMap()
-        contents[""] = inAssetsDir.list()
-        def tree = fileTree(dir: inAssetsDir)
-        tree.visit { fileDetails ->
-            if (fileDetails.isDirectory()) {
+    def newTask = task("cdvCreateAssetManifest") {
+      doLast  {
+          def contents = new HashMap()
+          def sizes = new HashMap()
+          contents[""] = inAssetsDir.list()
+          def tree = fileTree(dir: inAssetsDir)
+          tree.visit { fileDetails ->
+              if (fileDetails.isDirectory()) {
                 contents[fileDetails.relativePath.toString()] = fileDetails.file.list()
-            } else {
+              } else {
                 sizes[fileDetails.relativePath.toString()] = fileDetails.file.length()
-            }
-        }
+              }
+          }
 
-        outAssetsDir.mkdirs()
-        outFile.withObjectOutputStream { oos ->
+          outAssetsDir.mkdirs()
+          outFile.withObjectOutputStream { oos ->
             oos.writeObject(contents)
             oos.writeObject(sizes)
-        }
+          }
+      }
     }
     newTask.inputs.dir inAssetsDir
     newTask.outputs.file outFile