v4.0.0

This release leverages the shadowdom for improved ergonomics. This should be a drop-in change for the most part, but we've released it as a breaking release as it may require some changes to markup or CSS.

What's Changed

• add more examples to examples page by @keithamus in #72
• Simplify events by @keithamus in #73
• get example page axe clean by @keithamus in #76
• Refactor gettabs into private getters by @keithamus in #74
• Refactor setup code to call into selecttab by @keithamus in #75
• Refactor shadowdom by @keithamus in #77

Full Changelog: v3.4.0...v4.0.0