Update Html.php

fix

Author: troosan

src/PhpWord/Shared/Html.php

@@ -284,7 +284,7 @@ protected static function parseInput($node, $element, &$styles)
         $inputType = $attributes->getNamedItem('type')->value;
         switch ($inputType) {
             case 'checkbox':
-                $checked = ($checked = $attributes->getNamedItem('checked')) && $checked->value === "true" ? true : false;
+                $checked = ($checked = $attributes->getNamedItem('checked')) && $checked->value === 'true' ? true : false;
                 $textrun = $element->addTextRun($styles['paragraph']);
                 $textrun->addFormField('checkbox')->setValue($checked);
                 break;