86: feat: Use new asm! instead of llvm_asm! r=Disasm a=duskmoon314

The new `asm` macro has been merged into `nightly` for some time, while `llvm_asm` will be gradually deprecated and will not enter `stable`. This PR replaces `llvm_asm` with `asm`, but there are still some minor issues to discuss.

My reference are:
- [asm feature](https://doc.rust-lang.org/unstable-book/library-features/asm.html)
- [arch/cortex-m: change a few llvm_asm!s to asm!s](https://github.com/tock/tock/pull/2092)
- [Convert all uses of llvm_asm! to asm!](https://github.com/rust-lang/stdarch/pull/1052)

---

In the new `asm` feature, there are several options can set to optimize codes. [options](https://doc.rust-lang.org/unstable-book/library-features/asm.html#options-1

)

However, I'm not quite sure which options to set. (Sort of newbie to asm in rust)

Co-authored-by: Campbell He <hkp18@mails.tsinghua.edu.cn>

Tested and working in hardware

84: bump version to v0.7.0 r=Disasm a=almindor



Co-authored-by: Ales Katona <ales@katona.me>

83: update bare-metal and remove Nr trait r=Disasm a=almindor



Co-authored-by: Ales Katona <ales@katona.me>

80: add support for mprv r=almindor a=jwnhy



Co-authored-by: john <799433746@qq.com>
Co-authored-by: John Weston <18240025+jwnhy@users.noreply.github.com>

82: use --target in CI checks r=Disasm a=almindor



Co-authored-by: Ales Katona <ales@katona.me>

81: remove unused ci scripts r=Disasm a=almindor



Co-authored-by: Ales Katona <ales@katona.me>

73: Add additional binaries for floating-point ABIs r=Disasm a=TechnoElf

Fixes #69

Co-authored-by: TechnoElf <technoelf@undertheprinter.com>

79: Switch CI to Github Actions r=Disasm a=almindor



Co-authored-by: Ales Katona <ales@katona.me>