message: Added: npm reference to the github and developer docs
  ***What does this change do?***
  Added reference to the github repo
  Added reference to developer casperlabs docs
  ***Why is this change needed?***
  Improve DevX experience. Difficult to track it back to the code and
  docs when found on npm.
diff: "name": "casper-contract",
  "version": "1.0.0",
  "description": "Library for developing Casper smart contracts.",
  + "homepage": "https://docs.casperlabs.io/en/latest/dapp-dev-guide/index.html",
  + "repository": {
  + "type": "git",
  + "url": "https://github.com/casper-network/casper-node.git",
  + "directory": "smart_contracts/contract_as"
  + },
  "main": "index.js",
  "ascMain": "assembly/index.ts",
  "dependencies": {},
  