[TASK] Add LICENSE.txt to ext:redirects

Change-Id: I59846db22964a26f610a304fab85f570884b063d
Resolves: #83651
Releases: master
Reviewed-on: https://review.typo3.org/55438


Reviewed-by: Oliver Hader <oliver.hader@typo3.org>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Susanne Moog <susanne.moog@typo3.org>
Tested-by: Susanne Moog <susanne.moog@typo3.org>