[TASK] Update SwiftMailer to 5.0.1

Feature wise equal to 4.3.1, but now with MIT license.

Resolves: #51406
Releases: 6.2

Change-Id: Ie0cd306b544c2f56853ca7e16ba6cdd5cdf84a6e
Reviewed-on: https://review.typo3.org/23370
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn
Reviewed-by: Jigal van Hemert
Tested-by: Jigal van Hemert