v21.0.3

What's Changed

Bug Fixes

• Fix dropzone in Shadow DOM (#186) — thanks @rmaiersilldorff

Cleanup

• Replace deprecated substr() with substring() (#199)
• Remove IE9/IE/Edge workarounds (#200)

Infrastructure

• Add vitest unit tests (64 tests)
• Add GitHub Actions workflows for CI, Pages deployment, and npm publishing
• Add test coverage reporting to CI