SIP-4: Dependency Update Check API

SIP Number: 4
Title: Dependency Update Check API


Let me introduce the background for submitting SIP-4.

We usually manage the versions of dependencies. For example, in NPM, you can see the current versions of dependencies all at once by checking the package.json file. However, in SUI, there is no easy way to check the current versions (upgrade number and package id) of the dependency packages of a package. It is even more challenging
to check the latest version.

To solve this problem, I suggested SIP-4 for an API spec that the SUI Explorer can use to show all current versions and latest versions of dependencies of a package.