Почему Heroku не билдит проект?

-----> Node.js app detected
       
-----> Creating runtime environment
       
       NPM_CONFIG_LOGLEVEL=error
       NODE_ENV=production
       NODE_MODULES_CACHE=true
       NODE_VERBOSE=false
       
-----> Installing binaries
       engines.node (package.json):  12.x
       engines.npm (package.json):   unspecified (use default)
       
       Resolving node version 12.x...
       Downloading and installing node 12.20.0...
       Using default npm version: 6.14.8
       
-----> Restoring cache
       - node_modules
       
-----> Installing dependencies
       Installing node modules
       
       > [email protected] install /tmp/build_07506587_/node_modules/bcrypt
       > node-pre-gyp install --fallback-to-build
       
       [bcrypt] Success: "/tmp/build_07506587_/node_modules/bcrypt/lib/binding/napi-v3/bcrypt_lib.node" is installed via remote
       
       > [email protected] postinstall /tmp/build_07506587_/node_modules/nodemon
       > node bin/postinstall || exit 0
       
       Love nodemon? You can now support the project via the open collective:
        > https://opencollective.com/nodemon/donate
       
       added 345 packages in 12.092s
       
-----> Build
       Running build
       
       > [email protected] build /tmp/build_07506587_
       > npm run build --prefix client
       
       
       > [email protected] build /tmp/build_07506587_/client
       > react-scripts build
       
sh: 1: react-scripts: not found
npm ERR! code ELIFECYCLE
npm ERR! syscall spawn
npm ERR! file sh
npm ERR! errno ENOENT
npm ERR! [email protected] build: `react-scripts build`
npm ERR! spawn ENOENT
npm ERR! 
npm ERR! Failed at the [email protected] build script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm ERR! A complete log of this run can be found in:
npm ERR!     /tmp/npmcache.PuHFB/_logs/2020-12-22T08_40_00_486Z-debug.log
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! [email protected] build: `npm run build --prefix client`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the [email protected] build script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm ERR! A complete log of this run can be found in:
npm ERR!     /tmp/npmcache.PuHFB/_logs/2020-12-22T08_40_00_520Z-debug.log
-----> Build failed
       
       We're sorry this build is failing! You can troubleshoot common issues here:
       https://devcenter.heroku.com/articles/troubleshooting-node-deploys
       
       If you're stuck, please submit a ticket so we can help:
       https://help.heroku.com/
       
       Love,
       Heroku
       
 !     Push rejected, failed to compile Node.js app.
 !     Push failed

"scripts": {
    "start": "cross-env NODE_ENV=production node app.js",
    "server": "nodemon app.js",
    "client": "npm run start --prefix client",
    "build": "npm run build --prefix client",
    "client:install": "npm install --prefix client",
    "client:build": "npm run build --prefix client",
    "dev": " cross-env NODE_ENV=development concurrently \"npm run server\" \" npm run client\""
  },