chore: specify package manager and its version

Author: alexzhang1030

package.json

@@ -2,6 +2,7 @@
   "name": "ast-grep-vscode",
   "version": "0.1.7",
   "description": "ast-grep VSCode is a structural search and replace extension for many languages.",
+  "packageManager": "[email protected]",
   "keywords": [
     "ast",
     "ast-grep",