update watch task

.vscode/tasks.json

@@ -1,25 +1,16 @@
 {
-	// See https://go.microsoft.com/fwlink/?LinkId=733558
+	// See https://go.microsoft.com/fwlink/?LinkId=733558 
 	// for the documentation about the tasks.json format
 	"version": "2.0.0",
 	"tasks": [
 		{
-			"label": "compile",
-			"group": {
-				"kind": "build",
-				"isDefault": true
-			},
-			"command": "npm",
-			"presentation": {
-				"reveal": "silent"
-			},
-			"args": [
-				"run",
-				"compile",
-				"--loglevel",
-				"silent"
+			"type": "npm",
+			"script": "watch",
+			"problemMatcher": [
+				"$tsc-watch"
 			],
-			"problemMatcher": [],
+			"group": "build",
+			"isBackground": true
 		}
 	]
 }