message: fail hard when both a `now.json` and `package.json` file with "now" are present
  As discussed in the GH issue.
diff: @@ -125,9 +125,11 @@ module.exports = async function getMetadata(path, {
  name = deploymentName
  }
  - // merge in `package.now` if present, but have `now.json` take precedence
  + // if the project has both a `now.json` and `now` Object in the `package.json`
  + // file, then fail hard and let the user know that they need to pick one or the
  + // other
  if (pkg.now) {
  - nowConfig = extend({}, pkg.now, nowConfig)
  + throw new Error('Refusing to proceed with multiple Now configurations (`now.json` and `package.json`). Please pick only one, then try again!')
  }
  return {
  