Add php-connect and composer-script commands to README

This commit updates the README to include documentation for two important
commands that were implemented in the Makefile but not yet documented:

1. php-connect: Provides direct shell access to the PHP container, making
   it easier for developers to run commands, install packages, or debug
   issues directly within the container environment.

2. composer-script: Adds a flexible way to run Composer scripts with
   arguments, allowing users to execute custom scripts defined in their
   composer.json files without needing to construct complex Docker commands.

Both additions enhance the developer experience by providing more intuitive
and powerful ways to interact with the containerized environment. The
documentation now accurately reflects all available commands from the Makefile.

Author: nanoninja

README.md

@@ -384,6 +384,8 @@ The Makefile provides many helpful commands:
 | composer-install  | Install PHP dependencies                     |
 | composer-update   | Update PHP dependencies                      |
 | composer-autoload | Update the autoloader                        |
+| composer-script   | Run custom scripts defined in composer.json  |
+| php-connect       | Open an interactive shell in PHP container   |
 | test              | Run tests                                    |
 | code-sniff        | Check code style with PHP_CodeSniffer        |
 | phpmd             | Analyze code with PHP Mess Detector          |