feat: updating php targets to use [] instead of array()

[erunion]

Does what it says on the tin. Updates all PHP targets to use [] for arrays instead of array(). Also updates a few instances of NULL to the more consistent null.

[reynolek]

A benefit I can think of for keeping it to be array() is that it maintains support for php5 and array() still works in php7...That being said php5 is EOL as of Jan 2019.

[erunion]

I thought the same, but yeah PHP 5 isn't getting any new updates now so I don't think there's any reason to code against that expectation.