08_one-of-your-dependencies-babel-preset-react-app

터미널 창에 아래와 같은 메시지가 뜰때

One of your dependencies, babel-preset-react-app, is importing the
"@babel/plugin-proposal-private-property-in-object" package without
declaring it in its dependencies. This is currently working because
"@babel/plugin-proposal-private-property-in-object" is already in y
node_modules folder for unrelated reasons, but it may break at any 
babel-preset-react-app is part of the create-react-app project, whi
is not maintianed anymore. It is thus unlikely that this bug will
ever be fixed. Add "@babel/plugin-proposal-private-property-in-obje
your devDependencies to work around this error. This will make this
go away.

원인

babel-preset-react-app이 @babel/plugin-proposal-private-property-in-object 패키지를 사용하고 있지만, 이를 자신의 의존성에서 선언하지 않았다는 경고

해결

@babel/plugin-proposal-private-property-in-object를 개발 의존성에 추가

npm install --save-dev @babel/plugin-proposal-private-property-in-object