[TASK] Bump typo3/core-testing-php73 and typo3/core-testing-php81 with 81:rc5 raise
PHP 8.1 RC5 has been released, this bumps the image and uses the alpine php8.1rc5 docker image as base for the php81 core testing image now.
Also bump typo3/core-testing-php73 for released 7.3.32.