panic-semihosting should be v0.3.0 with latest nightly

[maxekman]

It failed with the error mentioned in: https://users.rust-lang.org/t/psa-breaking-change-panic-fmt-language-item-removed-in-favor-of-panic-implementation/17875

   Compiling panic-semihosting v0.2.0
error[E0522]: definition of an unknown language item: `panic_fmt`
  --> /Users/<user>/.cargo/registry/src/github.com-.../panic-semihosting-0.2.0/src/lib.rs:67:1
   |
67 | #[lang = "panic_fmt"]
   | ^^^^^^^^^^^^^^^^^^^^^ definition of unknown language item `panic_fmt`

Updating to v0.3.0 solves the issue.

[japaric]

Done in #33