message: Display proper error message if path doesn't exist
  This closes
diff: #!/usr/bin/env node
  // Native
  -const { resolve } = require('path')
  +const { resolve, basename } = require('path')
  // Packages
  const Progress = require('progress')
  @@ -263,6 +263,11 @@ if (deploymentName || wantsPublic) {
  let alwaysForwardNpm
  async function main() {
  + if (!fs.existsSync(path)) {
  + error(`The specified directory "${basename(path)}" doesn't exist.`)
  + process.exit(1)
  + }
  +
  let config = await cfg.read({ token: argv.token })
  alwaysForwardNpm = config.forwardNpm
  