PHP 7.3 Layer v3

* Add extensions to support Symfony
* Send redirect responses (3XX) to client instead of following them
* Add libonig to support mbstring extension
* Send request body regardless of HTTP method
* Build with updated lambci 'provided' image

PHP 7.1 Layer v10

* Send redirect responses (3XX) to client instead of following them
* Send request body regardless of HTTP method
* Build with updated lambci 'provided' image

* Check for webserver startup (cold start reduction)

* Initial PHP 7.3 support

* Check for webserver startup (cold start reduction)

* Add built-in support for mbstring, postgresql, and mysql

* Fix value of $_SERVER['PHP_SELF'] for routing behavior

PHP 7.1 Layer Version 6

* Fix sending body to PHP script when making a POST request

PHP 7.1 Layer Version 5

* Scan for ini configuration files in /etc/php-7.1.d/ of layers
* Scan for ini configuration files in /php-7.1.d/ of function code
* Support AWS Application Load Balancer request events

PHP 7.1 Layer Version 4

* Ensure php.ini is loaded from function package (/var/task/php.ini)
* Set extension_dir to /opt/lib/php/7.1/modules by default
* Remove base64 response encoding for non-ascii responses