v6.0.0

If you are upgrading: please see UPGRADING.md.

Changed

• Breaking: bump abstract-leveldown (15d5a9e) (Vincent Weevers)
• Breaking: drop node 8 (Level/community#98) (8502b34) (Vincent Weevers)
• Bump node-gyp from 6.x to 7.x (8bc5696) (Vincent Weevers)
• Bump standard from 14.x to 16.x (d39e232, 39e3ca3) (Vincent Weevers)
• Bump node-gyp-build from 4.1.x to 4.2.x (#708) (91711fa) (Vincent Weevers)
• Skip stack exhaustion test (55a33b1) (Vincent Weevers)

Removed

• Remove default export (Level/community#87) (686d685) (Vincent Weevers)