Release 3.0.0

Add support for TYPO3 v12
Drop support for TYPO3 v10/v11

Thanks to @spoonerWeb Thomas Löffler for the v12 compatibility!

New features, thanks to @Hawkeye1909

• allow submission of "empty" select value so that serverside validation can work, e.g. when using bootstrap_package
• fallback loading of recipient records from the currently displayed page, the pageUid setting for the field is thus optional and forms can be more reusable