[TASK] Raise dependency to EXT:restdoc 1.4.0

If using EXT:restdoc for working with interactive mode, version
1.4.0 (-dev) is now mandatory.

Change-Id: I8eef6575da1e04146cf9cadd9425e3d17375264a
Reviewed-on: http://review.typo3.org/34247
Reviewed-by: Xavier Perseguers <xavier@typo3.org>
Tested-by: Xavier Perseguers <xavier@typo3.org>