v0.2.1

fix(ci): set cross-linker for aarch64 Linux builds

ring's assembly files need the aarch64 cross-linker, not the host linker.
Set CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_LINKER and use aarch64-linux-gnu-strip.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>