Easy Digital Downloads - PDF Invoices 2.2.30

* Important: This is the last release for the PDF Invoices extension, please see [how you can migrate to the Invoices extension](https://easydigitaldownloads.com/blog/introducing-invoices-1-3-impress-your-customers-with-attractive-invoices/#existing-pdf-invoices-user).
* Fix: Hardened the PDF generation validation.
* Fix - EDD 3.0+: Improved compatibilty with Orders list table action.
* Dev: Removed unnecessary build files.
* Dev: Added the EDD Addon Tools, to standardize activation and integration process.

Fix: Update fallback font for languages using special characters.
Fix: Custom decimal separators are now used on all line items.
Fix: Required parameters no longer follow optional parameters (this fixes a deprecation notice in PHP 8).
Fix: Discount line does not show if a discount code was not used.
Fix: Remove the colored background from the fee amount on traditional and color templates.
Fix: Renewal discounts no longer display if they are 0.00.
Tweak: Discount line has been moved to show above taxes (if enabled).

Fix: Remove duplicated link and title text to avoid unnecessary repetition.
Fix: In some server configurations, invoice generation could fail with an image size error when using a logo.
Fix: Undefined property post_date errors.