Disallow PHP 7.x for TYPO3 6.2
When installing TYPO3 6.2 via Composer currently everything larger than PHP 5.3.7 is allowed which includes PHP 7.x and even future versions.
This should be restricted to PHP 5.x.
[TASK] Disallow Composer installation with PHP 7.x
TYPO3 6.2 is not compatible with PHP 7.x thus properly declare this
for Composer installations.
Reviewed-by: Wouter Wolters <email@example.com>
Reviewed-by: Nicole Cordes <firstname.lastname@example.org>
Reviewed-by: Andreas Fernandez <email@example.com>
Reviewed-by: Daniel Goerz <firstname.lastname@example.org>
Tested-by: Daniel Goerz <email@example.com>
Reviewed-by: Frank Naegler <firstname.lastname@example.org>
Reviewed-by: Christian Kuhn <email@example.com>
Tested-by: Christian Kuhn <firstname.lastname@example.org>