chore: revert tsup upgrade for now

Author: danielroe

packages/vite-plugin-checker/package.json

@@ -49,7 +49,7 @@
     "@vue/language-core": "~2.2.2",
     "meow": "^13.2.0",
     "stylelint": "^16.14.1",
-    "tsup": "^8.3.6",
+    "tsup": "^6.7.0",
     "typescript": "^5.7.3",
     "vls": "^0.8.5",
     "vscode-languageclient": "^9.0.1",