[RELEASE] Release of TYPO3 6.0.7

Change-Id: Ibfe25a1c9688601c4e1f514afd28f30c8b1ee083
Reviewed-on: https://review.typo3.org/22520
Reviewed-by: TYPO3 Release Team
Tested-by: TYPO3 Release Team
[TASK] Set TYPO3 version to 6.0.8-dev

Change-Id: I036e4f5e69e384be33b30505f62c5eb2511ee74e
Reviewed-on: https://review.typo3.org/22521
Reviewed-by: TYPO3 Release Team
Tested-by: TYPO3 Release Team