Add tasks.setCompleted

this lets us easily grep the code on where the task is completed

src/taskworker.js

@@ -59,12 +59,11 @@ initialize(function (error) {
         const resultCallback = (error, result) => {
             // Error object has properties with enumerable: false (https://mattcbaker.com/posts/stringify-javascript-error/)
             const progress = {
-                percent: 100,
                 result: result || null,
                 error: error ? JSON.parse(JSON.stringify(error, Object.getOwnPropertyNames(error))) : null
             };
 
-            tasks.update(taskId, progress, () => process.exit(error ? 50 : 0));
+            tasks.setCompleted(taskId, progress, () => process.exit(error ? 50 : 0));
         };
 
         TASKS[task.type].apply(null, task.args.concat(progressCallback).concat(resultCallback));