Pacakge.jsonの更新 (npm-check-updates) ref: https://qiita.com/ugdark/items/c97fa1c13d6c078b2f4f

file0.txt

$ npm outdated

Package            Current  Wanted  Latest  Location
truffle              4.1.3   4.1.5   4.1.5  study_solidity
zeppelin-solidity    1.7.0   1.8.0   1.8.0  study_solidity

file1.txt

$ npm install --save-dev npm-check-updates
$ ./node_modules/.bin/ncu 
Using ~ package.json
⸨░░░░░░░░░░░░░░░░░░⸩ ⠏ :
The following dependencies are satisfied by their declared version range, but the installed versions are behind. You can install the latest versions without modifying your package file by using npm update. If you want to update the dependencies in your package file anyway, run ncu -a.

 truffle            ^4.1.3  →  ^4.1.5 
 zeppelin-solidity  ^1.7.0  →  ^1.8.0 


$ ncu -a

file2.txt

$ rm -rf node_modules package-lock.json 
$ npm install