[TASK] Update Swift Mailer to 5.0.3

Change-Id: I2fdd722f56e69c2c6b2bae23d9944973eed3c066
Resolves: #55745
Releases: 6.2
Reviewed-on: https://review.typo3.org/27387
Reviewed-by: Stefan Neufeind
Reviewed-by: Markus Klein
Tested-by: Markus Klein
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring