Only one missing option is reported at a time

[danxmoran]

Using caseapp 1.2.0, if you have:

import caseapp._

case class ExampleOptions(
  foo: String,
  bar: Int
)

object Example extends CaseApp[ExampleOptions] {
  def run(options: ExampleOptions, arg: RemainingArgs): Unit = {
    println(options)
    println(arg)
  }
}

If you run without arguments, you see:

$ sbt -error run
[error] Required option --foo not specified

Which is correct, but it'd be awesome if both --foo and --bar were reported missing.

[danxmoran]

I've got a fix for this; will push it once I do some cleanup!