package/php: security bump version to 7.3.6

Release notes: https://www.php.net/archive/2019.php#id2019-05-30-1

Fixes
CVE 2019-11038: https://bugs.php.net/bug.php?id=77973
CVE 2019-11039: https://bugs.php.net/bug.php?id=78069
CVE 2019-11040: https://bugs.php.net/bug.php?id=77988



Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>