[TASK] Release version 1.8.1

Resolves: #63359
Releases: 1.8
Change-Id: I30d16894b413eb62f43c2d5638c746eb620304d8
Reviewed-on: http://review.typo3.org/34680
Reviewed-by: Francois Suter <francois@typo3.org>
Tested-by: Francois Suter <francois@typo3.org>