refactor: extract userAgent constants

Author: dominykas

lib/constants.js

@@ -0,0 +1,6 @@
+'use strict';
+
+const Package = require('../package.json');
+
+
+exports.userAgent = `${Package.name}/${Package.version} (${Package.homepage})`;

lib/loader/npm.js

@@ -1,8 +1,8 @@
 'use strict';
 
-const Package = require('../../package.json');
 const Pacote = require('pacote');
 
+const Constants = require('../constants');
 const RepositoryLoader = require('./repository');
 
 const internals = {};
@@ -27,7 +27,7 @@ exports.create = async (packageName) => {
     try {
         const packument = await Pacote.packument(packageName + '@latest', {
             'fullMetadata': true,
-            'user-agent': `${Package.name}@${Package.version}, see ${Package.homepage}`
+            'user-agent': Constants.userAgent
         });
 
         const repository = internals.parseRepository(packument);