chore: use target-cpu=native by default

[skyzh]

Signed-off-by: Alex Chi [email protected]

To verify this really works, run rustc in project root:

> cargo rustc --print=cfg -Z unstable-options
debug_assertions
panic="unwind"
target_abi=""
target_arch="x86_64"
target_endian="little"
target_env="gnu"
target_family="unix"
target_feature="adx"
target_feature="aes"
target_feature="avx"
target_feature="avx2"
target_feature="bmi1"
target_feature="bmi2"
target_feature="cmpxchg16b"
target_feature="ermsb"
target_feature="f16c"
target_feature="fma"
target_feature="fxsr"
target_feature="lzcnt"
target_feature="movbe"
target_feature="pclmulqdq"
target_feature="popcnt"
target_feature="rdrand"
target_feature="rdseed"
target_feature="rtm"
target_feature="sse"
target_feature="sse2"
target_feature="sse3"
target_feature="sse4.1"
target_feature="sse4.2"
target_feature="ssse3"
target_feature="xsave"
target_feature="xsavec"
target_feature="xsaveopt"
target_feature="xsaves"
target_has_atomic="16"
target_has_atomic="32"
target_has_atomic="64"
target_has_atomic="8"
target_has_atomic="ptr"
target_has_atomic_equal_alignment="16"
target_has_atomic_equal_alignment="32"
target_has_atomic_equal_alignment="64"
target_has_atomic_equal_alignment="8"
target_has_atomic_equal_alignment="ptr"
target_has_atomic_load_store="16"
target_has_atomic_load_store="32"
target_has_atomic_load_store="64"
target_has_atomic_load_store="8"
target_has_atomic_load_store="ptr"
target_os="linux"
target_pointer_width="64"
target_thread_local
target_vendor="unknown"
unix