이런 에러는 왜 생기는건가요?

(node:17608) [DEP0148] DeprecationWarning: Use of deprecated folder mapping "./" in the 

"exports" field module resolution of the package at C:\Users\oksos\Desktop\study\PTE\loginWeb\client\node_modules\postcss-safe-parser\node_modules\postcss\package.json.        

Update this package.json to use a subpath pattern like "./*".

(Use `node --trace-deprecation ...` to show where the warning was created)

createProxyMiddleware is not a function