Update to 9.5.12

Changelog: https://typo3.org/article/typo3-10-2-1-9-5-12-and-8-7-30-security-releases-published

PR: 242708
MFH: 2019Q4
Security: 1c9178aa-2709-11ea-9673-4c72b94353b5
Sponsored by: Netzkommune GmbH