Install yarn error:

yarn install v1.21.1 warning package-lock.json found. Your project contains lock files generated by tools other than Yarn. It is advised not to mix package managers in order to avoid resolution inconsistencies caused by unsynchronized lock files. To clear this warning, remove `package-lock.json`. – [1/5] Validating package.json… – [2/5] Resolving packages… – [3/5] Fetching packages… info…