Update README.md

[rleppink]

cargo init creates a Rust project in the current directory. This means the tutorial has a wrong order of operations for getting started.

It should be either:

1. cargo new and the line below says (currently correctly) "cd into your new directory", or
2. mkdir leptos_tutorial, cd into your new directory, then cargo init

[gbj]

For me, cargo init leptos-tutorial creates a directory named leptos-tutorial inside the cwd, which I can then cd into. Does cargo behave differently for you?

Per Cargo docs:

This command will create a new Cargo manifest in the current directory. Give a path as an argument to create in the given directory. (my emphasis)