Downgrade vsce to bundle Python scripts.

The Python scripts is missing due to this issue:
microsoft/vscode-vsce#576.

Fix #125.

Author: seanwu1105

package-lock.json

@@ -40,7 +40,7 @@
     "prettier": "^2.3.0",
     "ts-loader": "^9.2.2",
     "typescript": "^4.3.2",
-    "vsce": "^1.92.0",
+    "vsce": "~1.91.0",
     "vscode-test": "^1.5.0",
     "webpack": "^5.38.1",
     "webpack-cli": "^4.7.0"