CommandArguments::options() breaks multivalue options

[geek-merlin]

Steps to reproduce

Generate an exec line via something like

$options = [
  'multioption' => ['foo', 'bar']
];
$this->taskExec()->options($options, '=')

(via https://github.com/openeuropa/task-runner)

Expected behavior

mycommand --multioption=foo --multioption=bar

Actual behavior

mycommand --multioption=Array

[geek-merlin]

Looked into patch of #1038 but it does not touch that.

[greg-1-anderson]

This is a feature request. PRs welcome.