add prepublishOnly script

Author: bradlc

packages/tailwindcss-language-service/package.json

@@ -11,7 +11,8 @@
     "start": "tsdx watch",
     "build": "tsdx build",
     "test": "tsdx test",
-    "lint": "tsdx lint"
+    "lint": "tsdx lint",
+    "prepublishOnly": "npm run build"
   },
   "dependencies": {
     "@ctrl/tinycolor": "3.1.4",