feat: add version and color

[baszalmstra]

Adds --version, usage, about, and stuff to Cargo.toml.

A package management and workflow tool

Usage: pixi.exe [COMMAND]

Commands:
  completion  Generates a completion script for a shell
  init        Creates a new project
  add         Adds a dependency to the project
  run         Runs command in project
  install     Installs the defined package in a global accessible location
  help        Print this message or the help of the given subcommand(s)

Options:
  -h, --help     Print help
  -V, --version  Print version

Fixes #92

[pavelzw]

pixi.exe is only used on Windows.

[baszalmstra]

Its autogenerated by clap so it will be different per OS. But I removed the exe from the readme.