fix(bundlers): remove browser field in package.json to enable tree shaking
fix(bundlers): remove browser field in package.json to enable tree shaking

Starting Angular CLI 6.x, no empty modules are supplied for node globals, see:
https://github.com/angular/angular-cli/issues/9827
https://github.com/contentful/contentful.js/issues/260
contentful/contentful-management.js,contentful/contentful-management.js