[RELEASE] Add support for TYPO3 v12/v13/v14

What's Changed

• [TASK] Update README by @davidsteeb in #1
• [BUGFIX] make composer.json valid by @achimfritz in #3
• [TASK] Update extension for v12 or higher by @lkreitz in #5

New Contributors

• @davidsteeb made their first contribution in #1
• @achimfritz made their first contribution in #3
• @lkreitz made their first contribution in #5

Full Changelog: 1.1.2...2.0.0