Release v3.0.0

What's Changed

Updated Node SDK to support Intercom APIs > v2.x
Removed methods deprecated in API v2.x
Removed support for callbacks and replaced it solely with promise-based approach
Add >90% API coverage
Updated dependencies

What's Changed

• [Beta Release] merged by @hypeofpipe in #289

Full Changelog: v3.0.0-0...v3.0.0