Install notes in releases are not specific enough to each platform

[pierremtb]

https://github.com/KittyCAD/cli/releases

We just had a user at the makeathon failed to install the zoo cli on their own due to curl not being able to download to /usr/local/bin on macOS (needed sudo) and @lf94 and I had to jump in and help.

The notes for Windows also seem not plausible (bash syntax and unix paths)