doc: update README.md install instructions

README.md

@@ -48,10 +48,12 @@ Assuming you have a Nordic nrf52840dk connected, this should get you somewhere:
 1. install [laze](https://github.com/kaspar030/laze): `cargo install laze`
 
 1. install [probe-rs](https://github.com/probe-rs/probe-rs): `cargo install probe-rs --features cli`
-   (2023-10-17: if that fails, try from git: `cargo install --git https://github.com/probe-rs/probe-rs --features cli`)
+   (2023-10-17: if that fails, try from git: `cargo install --git https://github.com/probe-rs/probe-rs --features cli probe-rs`)
 
 1. clone this repository and cd into it
 
+1. install rust targets: `laze build install-toolchain`
+
 ### Run some example
 
 1. Compile, flash and the hello-world example using `probe-rs run`