DateType widget 'single_text'

[trickreich]

                DateType::class,
                [
                    'widget' => 'single_text',
                    'format' => 'dd/MM/yyyy',
                    'html5' => false,
                    'attr' => [
                        'placeholder' => 'form.possible_work_beginning',
                        'class' => 'js-datepicker'
                    ],
                    'required' => false,
                    'error_bubbling' => true,
                ]