chore: release 0.2.1 - widen @oven/bun-* version range (#176)

* fix: widen @oven/bun-* version range to improve install compatibility

Lower the minimum version of @oven/bun-* optional dependencies from
^1.3.4 to ^1.2.21. This is the lowest common version available across
all platform-specific packages, improving compatibility for contributors
who may not have access to the latest package versions.

The caret range (^) still allows npm to install newer versions when
available.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

* chore: bump version to 0.2.1

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

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Co-authored-by: Claude <[email protected]>

Author: ochafik