update plugin headers

[dpanta94]

All Submissions:

• [x] Does your code follow the Extendables standards?
• [ ] Have you written new tests for your changes, as applicable?
• [x] Have you successfully run tests with your changes locally?

Changes proposed in this Pull Request:

COMMENT TO BE UPDATED

Closes woo#224.

How to test the changes in this Pull Request:

Performed the following tests.

• Place order (Classic and Express):
  • Simple product (physical and virtual)
  • Subscriptions (physical, virtual)
    • with Sign up fee
    • with trial period
    • Upgrade & downgrade
  • Multicurrency orders for (EU and UK Region)
  • Renew order of Subscriptions
  • Dynamic pricing on orders
• Refund:
  • Full/Partial Refund from admin
  • Full/Partial Refund from Seller account (receiving the IPN)
• Onboarding (connect account)
  • Automatic import key during onboarding process
  • Manual import keys

Other information:

• [x] Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changelog entry

Tweak - TO BE UPDATED

[dpanta94]

Merged y pull#231