fix: Flat config TypeScript fix

Fixes TypeScript types for CJS usage of flat config.

Fixes #299

Author: mskelton

package.json

@@ -30,7 +30,7 @@
     "dist"
   ],
   "scripts": {
-    "build": "tsup src/index.ts --format cjs,esm --dts --out-dir dist",
+    "build": "tsup src/index.ts --format cjs,esm --dts --out-dir dist --cjsInterop",
     "lint": "eslint .",
     "fmt": "prettier --write .",
     "fmt:check": "prettier --check .",