Support cli tools which feature detect ansi color support

[staabm]

Describe the enhancement
When running php based cli tools within a action, the color detection support does not work.
Most php cli tools are based on symfony/console which relies on a stream_isatty check to auto activate ansi color support.

I would expect GithubActions to support a running context which makes tools aware that ansi colors are supported and so they realize it and automatically use it.

My examples all mention php, but I guess a lot of tools (even non php) use a isatty-like check for feature detection.

Code Snippet
Use a php based project which contains a composer.json and run composer install.
Atm this does not support coloring and we need to force enable coloring with composer install --ansi which is tedious

Additional information
Also reported to composer at composer/composer#9269