Missing sccache when checking tooling

[bodinsamuel]

hi,

I tried to install citybound for the first time today. The contributing guide is clear and helpful 👌
I think it's just missing a check on sscache (or a dependency not sure yet how everything works)

λ npm start
error: failed to run `rustc` to learn about target-specific information

Caused by:
  could not execute process `sccache rustc - --crate-name ___ --print=file-names --crate-type bin --crate-type rlib --crate-type dylib --crate-type cdylib --crate-type staticlib --crate-type proc-macro` (never executed)

npm start works after doing cargo install sccache