Merge #65

65: Update `riscv` crate to version 0.6 r=Disasm a=luojia65

This pull request solves a probable version conflict between latest `riscv` and `riscv-rt`.

The MSRV is also updated to 1.42.0, since the 0.6.0 version of `riscv` crate requires 1.42.0: [link](https://github.com/rust-embedded/riscv/blob/6392fa9520b042bd559b00b9c7131b6de4189f89/CHANGELOG.md#changed

).

This pull request also includes a small typo fix in changelog file.



Co-authored-by: luojia65 <me@luojia.cc>