package/php-xdebug: add zlib optional dependency

zlib is an optional dependency (enabled by default) since bump to
version 3.2.0 in commit 8280400fbadde09e51ccff312d7a4ef6a386f589 and
https://github.com/xdebug/xdebug/commit/3954e5cd9e48eec0a8a2a0c6a2fc120bbe562656

Fixes: 8280400fbadde09e51ccff312d7a4ef6a386f589

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
1 file changed