chore: add deploy script for Open VSX to package.json

Author: jokroese

package.json

@@ -140,6 +140,7 @@
     "build": "pnpm run lint && node esbuild.js --production",
     "dev": "pnpm build -- --watch",
     "deploy:extension": "vsce publish --no-dependencies",
+    "deploy:openvsx": "ovsx publish -p $OVSX_PAT",
     "lint": "eslint src --ext ts"
   },
   "devDependencies": {