v7.0.0-rc.2

Breaking changes:

• Drop Node.js v6 support - #818

Features:

• Custom http agent support - #810
• Support for publish_address as hostname/ip:port - #804
• Use Elasticsearch 7.0.0 - #820

Enhancements:

• Improve typings - #813 #819

Documentation:

• Fix a typo in usage example - #806