[vscode] Fix required engine version

Author: dinvlad

client/vscode/package.json

@@ -11,7 +11,7 @@
   "icon": "images/openwdl.png",
   "private": true,
   "engines": {
-    "vscode": "^1.34.1"
+    "vscode": "^1.56.0"
   },
   "categories": [
     "Programming Languages",