issue 3468090:add option drupal in type field of tag.twig

adding 'drupal' in starshot_demo/components/01-atoms/tag/tag.twig for type variable. This fixes Issue 3: In starshot.component.yml, There is a property 'type' inside tags array.

starshot_demo/components/01-atoms/tag/tag.twig

@@ -5,7 +5,7 @@
  *
  * Variables:
  * - theme: [string] Theme: light, dark.
- * - type: [string] Type: primary, secondary, tertiary
+ * - type: [string] Type: primary, secondary, tertiary, drupal
  * - content: [string] Content.
  * - icon: [string] Icon name.
  * - icon_placement: [string] Icon position: before, after.