message: fix(exchange): add main section to package.json
diff: "author": "EnergyWeb DevHub GmbH; Piotr Kosinski, piotr.kosinski@energyweb.org",
  "license": "GPL-3.0",
  "private": true,
  + "main": "dist/js/src/index.js",
  "repository": {
  "type": "git",
  "url": "git+https://github.com/energywebfoundation/origin.git"
  "@energyweb/exchange-token-account": "0.1.0",
  "@energyweb/utils-general": "7.0.0",
  "@energyweb/issuer": "0.11.0",
  + "@energyweb/origin-backend-core": "1.2.0",
  "@nestjs/common": "6.11.6",
  "@nestjs/config": "0.2.2",
  "@nestjs/core": "6.11.6",
  