Seaport 1.6

This release contains the core contracts for Seaport 1.6.

What's Changed

• Seaport 1.6 Updates by @0age in #15
• second round of 1.6 changes by @0age in #16
• add badges to README.md by @ryanio in #17

New Contributors

• @ryanio made their first contribution in #5

Full Changelog: 1.5.0...v1.6.6